Perhaps find a frame you can swap things to for the time being? Something in the aluminum or steel category if you're really worried. I'm at your weight and do have a carbon fork on my bike which I don't have any trepidation about riding and would suspect that your bike's owners manual may say if there is an issue. On nicer bikes I've had the manuals state no sitting on top tube, one capped out weight at 250lbs and one that said the warranty was void if the bike was used for purposes other then racing, I assume training races counted with that. If not call the company and ask. If I was really worried I'd drop a grand on a bike to ride on like a fuji roubaix and just keep it as a backup when/if I didn't need it anymore.