I remember I was on Mepron it kicked my butt. I tried to ride it out thinking it was doing something, i.e. getting infection out but it was a challenge, I did pretty good I think I stayed on quite awhile, I do remember I would take a couple of days off of anything that was making me too sick Bactrim was a witch too. I don't think it is anxiety causing symptoms I think its either because antibiotic is doing its job and causing die off making one very sick (I abhored heart pounding) or it could be a reaction to the actual antibiotic. Maybe cut back a couple of days gather some strength, my Lyme dr, always told me this. We want the poison to die off but we would rather it not take us with it!