How To Deal With A Clingy Boyfriend?

Okay, so this explanation might be a little long so bear with me...So me and this guy have been together for nearly a year now..I waited about 8 months before making it official between us because I had JUST gotten out of a relationship when I met him. Well we started off spending A LOT of time together, he was always calling and checking up on me, he always wanted me to go out with him and at first it was nice..he's a fun guy, he has a great job and seemed so sweet and treated me good. Now, over time I'm noticing that he's really just clingy. He's always calling me when he's at work (normally at least 8 times a day) he ALWAYS wants me over (EVERYDAY!) and if I say "Well maybe we should spend tonight apart" he throws such a fit and acts like I'm telling him I never want to see him again, he pops up at my house UNANNOUNCED which he knows drives me crazy, he always talks about wanting me to move in and he blames me for him losing his friends when I NEVER tried to keep him all to myself, he also refuses to let me go out to any clubs with my girlfriends by myself. He lost his mother about 5 years ago so I think that may play a part in why he acts like this at his age (he's 28, I'm 22) He always thinks that I'm going to leave him, he seems to not believe me when I tell him I love him or miss him (He'll reply with "yeah right") I mean I really do love him but I don't know how to deal with this. I'm starting to think he's bipolar or something and I'm afraid I may have ignored the warning signs with this one and don't know what to do now. It seems he's so stuck in his ways he won't change, but I want to at least get some advice. Thanks!