I hate to say this, but every time I'm on an antibiotic, I seem to lose a little more GI function. I think antibiotics are much more serious meds than they are treated.
Try changing your probiotic, or take one type in the a.m., and a different one in the p.m. or the next day. I think its good to try all different strains. Hang in there. Hopefully, you'll eventually get back to "normal".