Republicans are very good at empowering their followers to speak out, and they do, loudly and frequently. Add to that all the right-wing radio and Fox news giving them specific talking points day in and day out and it's easy to sometimes feel as if everyone is a rightwinger.
You said you have around 200 Facebook friends but only mentioned a handful who said negative things about Obama. There's a very good chance that some of the silent ones also like Obama but keep quiet because they also feel like they are in the minority.
I read a blog from a guy who is a moderate and posts mostly non-political posts. When he occasionally mentions anything political, he immediately gets a bunch of comments about how horrible Obama is, how he's ruining America, etc. I use to get depressed reading it and thought I was the only one from his group of readers who likes Obama. One day, after reading a bunch of "Obama sucks" posts I decided to speak up. I didn't rant, I just said I liked Obama and thought he was doing a pretty good job considering what he had faced. Then, I mentioned a few thing he had done that I liked. The response shocked me. Suddenly others were commenting that they liked him, too. It was like a damn burst. I guess no one wanted to be the first person to defend him and just assumed that they were the only one who felt that way.
Millions of people voted for Obama. In the reddest of red counties, there are still thousands of people who voted for him. Republicans encourage their supporters to be loud and obnoxious because they know that works to make the rest of us shut up. Don't be afraid to speak up! You're not alone, they just want to make you think that you are.