It depends really heavily on your background. As a garment worker in a large city like New York or Chicago you are likely an Italian or Jewish immigrant. You are unlikely to speak English well, you are likely bi or tri lingual, and it is likely you are able to read a little bit. I you are Jewish, you are likely to eat kosher. Either way you are likely to eat the American equivalent of your traditional foods. Your diet is probably heavily bread based, though you will have significantly more access to meat and fish than someone living in Europe or Great Britain. You may have been provided food for lunch at your place of work, but you also might go home for a mid-day meal or eat in a nearby cafeteria which catered to female factory workers. You may have brought a pack lunch but this was more common among agricultural workers. Sometimes small factories were set up in people's tenement homes, so you may have lived, worked, and eaten in the same place. If you had a lunch break you may have gotten food such as pickles, knishes, or chestnuts from a nearby pushcart. It would not have been acceptable for you to dine with men outside your immediate family, and some would frown upon you eating in the street. Your home most likely did not have what we would call a full kitchen, though you would likely have access at least to a shared sink and stove, either in your home, or shared between tenements. You likely did not have running water, and you almost certainly did not have electricity, an unshared, indoor toilet, or hot running water. Anything that required refrigeration had to be bought in small amounts, in order to be used before it spoiled. Almost all your wages would go to food and rent. You as a single woman would likely be contributing to a family budget, with one or both of your parents and any number of your siblings contributing as well. You were much more likely to live with family than in a boarding house, unless you had no family in the area. Your household likely spent at least 1/3 of your income on food.
You may have started your day with hot or cold cereal, a new and very American addition. Or you may have some sort of bread, most people had coffee or tea with breakfast, and children were often given milk. Dairy was often delivered, that would include milk, cream, and butter, you may have had any or all of these if you could afford them, none if not. Bread may have been eaten plain, or with a spread most likely drippings or butter. If you weren't Jewish, drippings were most likely from bacon, one of the cheaper and most popular meats. You had meat, chicken, or fish anywhere from once a day, to once a week depending on your income. Much of your meat was likely processed, and you would have been fairly careful about what meat you acquired, as regulations for the safety of meat was only just beginning. You were also likely to be having some processed foods, mostly boxed or canned. Boxed, cold breakfast cereals were fairly cheap and the height of fashionable modernity.
If you were Italian, your largest meal of the day would be starting to look more like Italian American food of today, than the heavily regional food of Italy. You were likely eating pasta, a good deal of garlic, and red sauces. You were also likely to have access to an Italian delicatessen.
If you were Jewish, you would also eat delicatessen, though of a very different variety. You would likely have a diet with some fish, such as herring, dairy foods like sour cream, and your family was likely to save money to have chicken on Friday evenings. Pickles came in many varieties, and things like bialys, bagels, knishes, and other traditional foods could be bought from the dozens of pushcarts around the Lower East Side.
For the poorer classes street food was popular, hot dogs, hot pretzels, pickles, chestnuts, and even oysters were popular among the working classes. Pickles, and spiced meats like salami, pastrami, or the many heavily spiced Italian deli meats were looked down on by the American born, white middle and upper classes as their garlic and bursting flavor were considered bad for the digestion. However these foods were likely fairly central to your diet, especially at lunchtime. Because you likely worked long hours, lunch was the largest, most important meal of the day. If you had 5 or 10 cents you may have eaten at one of the new lunch counters, automats, and luncheonettes where you could get a hot, american style meal and coffee for a fairly affordable price. Think sandwiches, soup, mashed potatoes, etc.
You were likely able to afford an occasional treat, something between 1 and 10 cents, and you would likely get these at a soda fountain, probably getting ice cream, italian ice, or a soda such as an egg cream. You also probably ate a good deal of "ethnic" foods that were actually created in the US such as spaghetti and meatballs, along with traditional foods from your home country. You may have been pressured to eat blander, more "American" foods like boiled meat and vegetables by those advocating assimilation.
https://www.theatlantic.com/business/archive/2016/02/america-in-1915/462360/
Pastrami Land by Harry Levine
https://www.lagazzettaitaliana.com/food-and-wine/7627-a-brief-history-of-italian-food-in-america
https://blog.oup.com/2016/10/immigrants-food-america/
https://journals.sagepub.com/doi/abs/10.1525/ctx.2007.6.3.67
http://www.digitalhistory.uh.edu/topic_display.cfm?tcid=92