One thing is you may just not be fast enough right now. Just keep going out and try to hang on a little longer next time. Don't let it discourage you. When I started road riding I did it with the fastest group ride around. I got dropped, and dropped, and dropped, and dropped some more. Then, one day, I could keep up. You will get faster by riding with people that are better than you.
Like the Fixer said, learn the fine art of wheel sucking.
You use up to 30% less energy in the draft. You cannot afford to push your own wind until you get faster. If you break the draft, you are gone.
Get out there and take your lumps. It will pay off.
