Sick with a cold!

I am 10 weeks pp and exclusively breast feeding a gorgeous baby boy. However I caught a cold and I am taking Tylenol as recommended by my doctor but it seems like my milk supply is dwindling! Baby won't stpp crying for hours on end and I ended up giving him some formula I got as a sample from Similac and he finally seemed satisfied. I can still manage to breast feed him cor about 10 mins per breast but even then he doesn't seem completely satisfied. Could it be my body is unable to keep up with milk supply with my sickness, that it will come back to normal once I'm over my cold, or is that it for me breast feeding?? I am so confused..