Girl, I say, whatever you are doing is enough. Something is always better then nothing.
With that being said, I say go to the gym. The heck with those guys and girls whom you think might be looking at you. I was the same way. I was 330 pounds when I started this journey. I work at the local University and we have a gym also. It is usually packed full of the hot buff college kids. But let me tell you how suprised I was when those same kids after being there a week, started offering great advise. You may THINK you are being watch, I DID, but in all reality, your not. Give it shot and go for it.