Ive read some history accounts that paint Stalin as being totally shocked and emotionally crushed that his "friend" Hitler decided to back stab him. Ive read that he locked himself in the room and would not talk to folks for 3 days.
Was he really that shocked? Wasn't he planning the same move against Hitler or did he truly believe in the dual ownership?
First of all let me say that Stalin didn't leave a diary so we can't exactly say what his emotions or personal thoughts were with confidence. That said, he was probably neither of those things.
The idea that he locked himself in a room for 3 days is certainly not true. We do have a record of his itinerary of the first day after the German invasion. Stalin spent the entire day meeting senior officials and generals, from before 6am to after midnight. He continued to have a fairly busy schedule that entire week. Nor could we say that he was really "shocked". Under a cover of military exercises, the Red Army began to mobilize before the Germans had invaded and certain units were ordered to move toward the border. A special directive was issued to the troops that an imminent attack was likely. All of these steps were significantly belated - mobilization should have began nearly a month prior. To say that Stalin was completely shocked would be misleading. Also to say that Stalin and Hitler were "friends" is a bit preposterous - the two have never met or even interacted directly.
That said you COULD make a case that Stalin fell into a state of despair or panic slightly later, about a week after the war began, when it became clear that things were developing catastrophically, the city of Minsk had fallen, and that war might be lost. He retreated to his dacha outside of Moscow, and didn't see people for a period of 3 days. Stalin is described as depressed. When several senior officials came to visit Stalin, upon seeing him he supposedly thought they came to arrest him. However this hypothesis, too, is tenuous. Stalin frequently worked in his dacha, so him being there isn't really evidence of him trying to hide. Almost all evidence comes down to memoirs of a single person, Anastas Mikoyan. Unlike several people who later wrote about Stalin's possible depression, such as Khrushchev, Mikoyan was the only one actually on the scene. It is certainly possible that Stalin was feeling down after receiving terrible news from the front. Anthony Beevor writes that Stalin even floated the idea to offer huge swaths of western USSR (including Ukraine and Belarus) to Hitler in exchange for peace but was then dissuaded of this. In short, it seems that Stalin was more affected by how poorly the war was going rather than the start of the war itself. Beyond that, there isn't a whole lot of evidence to go on, beyond a couple memoirs and speculations of Stalin's associates.
Lastly, there is the idea that Stalin himself was about to invade Germany and that Hitler just preempted him. This hypothesis was popularized by a former Soviet spy who wrote under a pseudonym Viktor Suvorov. However, almost no reputable Russian or western historian supports this idea. While it is definitely possible that Stalin planned to eventually attack Germany, it is extremely unlikely that would have happened that year. The Soviet military was undergoing wide-sweeping reforms and reorganization and was in no shape for a major war at the time.
EDIT: My first gold ever - thank you kind sir/lady!
Isn't it true that Stalin made several attempts to form alliances with the Western powers against the radically anti-communist Hitler and was rejected every time? And the pact with Hitler was really a temporary last ditch effort to protect the USSR?