Is this guy gay?

Hello, Im Mike.In my University there's a guy who I recently met (3 months ago) we got a lot of classes together, the thing is that one day he put his backpack in my seat and I, joking, asked him "Do you wanna fight?" he (Lets say Mark) answered "Why would I fight with someone i like so much". Other day I helped him with a class sending him pictures of class material via Whatsapp, and he answered "Dude, I love you" and put that big heart emoji. Also everytime he greets me put his hand in my shoulder, or my back, or my arm; once I caught him staring at me like for 30 secs (i know it because i was talking to a girl and in the background it was him, i was aware of him), once in class i was in my seat and rested my face above my forearms, and i felt someone put his hand on my head and almost instantly put off, when I looked it was him passing by. The last thing was today in class; I helped a friend (Mark's friend) to pass some videos to a pc, Mark appeared and said "Mike is a really good boy" while he put his hand in my shoulder, then my neck, then my nape hair brushing it with his hands and then and massaged me like for 7 secs.I've seen him hugging his friend, just hugging, but with me there is all that stuff. Am I overreacting? Are there straight guys who also make that stuff?I've listened that he had a girlfriend who left him before going to the university.