feeding moms I need your help re: thrush from antibiotics?

I'm just getting over a really bad case of mastitis and I am on antibiotics and I think I might have thrush over the last few days my have become really sore and cracked and I think I have a "milk blister " on it from the thrush it's really painful to nurse the side and inbetween feedings I have this really deep pain kind of like the pins and needles feeling when you letdown but worse. Im scheduling an appt today but my dr. is an idiot so how do I know for sure I have it. My baby does not show any signs yet like no patchy white stuff in mouth or no diaper rash can it take several days for those signs to show in him? I have been on the antibiotics for about 4 days today being the 5th and I just dont want it to get worse. Thanks any input will help like your syptoms when you had thursh did baby have them too? Thanks