AWFUL diarrhea after vax (contains pic)

Okay so my daughter is 9 weeks old today. She got her 2 month vaccinations on Wednesday (Rotavirus, HiB, Pneumococcal, and DTaP). She is also on the antibiotic Cefdinir (since last Monday for a UTI). She has been having AWFUL watery diarrhea. It ends up all down her legs and up her back and stomach and I find myself changing her 5-6 times a day and cuddling her up in a towel instead of a blanket as to not ruin everything she owns with poop! We have a doctor appt at 6pm tonight, but I just wanted to get others' thoughts. I've done some googling (I know, terrible lol) and I found everything from normal to C. Diff to rush her to the ER. Lol any thoughts??