I was having similar feelings lately as well. I went to a therapist who explained to me I was experiencing a case of heavy Depression / Anxiety, he also explained that it was quite common. My suggestion is you go see someone, just so you can talk to somebody about it. I can't speak for everyone, but it helped me quite a bit. Just don't turn to self medication, that's a dangerous path.
I happen to have a birthday on the launch date, so I'm a little bitter I can't have a party since everyone i know will be playing Diablo 3. That and I was hoping torchlight 2 would have been out by now.
Even since Itagaki left Team Ninja, all the talent seemed to have went with him. I wasn't expecting anything from Team Ninja is now, but man they sure surprised me with how bad this seems. They didn't get me with Metroid: Other M and nothing so far makes me when to get Ninja Gaiden 3. (Loved the first two, but *bleck* to this 3rd one). Here's hope for Devil's Third.
In a way it has been somewhat enjoyable talking about and coming up with theories. My big sticking point for this is that is ending's agency for story telling was drastically unlike anything in the series, vague and brief. So I guess in a way bringing myself to interpret everything I guess made my own ending the way I wanted it be. Similar discussions come up in things like film and fine art. It's been kind of cool, but the big issue is whether Mass Effect's fan-base was the right place for this.