Baby sleep-opinions please!

My 7 week old baby will ONLY sleep on my arms, or across my chest. Every time I put him down he wakes him self up. We have tried the swing, and the bassinet. I've tried swaddling, and he HATES it. He loves to sleep with his hands touching his face so the swaddle just makes him mad. Today I laid him in his bassinet on his stomach just to see what he'd do and he slept!!! I literally sat there and watched him sleep because I was so nervous leaving him on his belly, but It looks like we have a stomach sleeper,  but I know it's "back to sleep"... What should I do?!