Help!

My dentist prescribed me amoxicillin for an infection a week ago , but since taking the medication I have had the worst yeast infection. I tried calling up to my ob/gyn office a few times , but all I get is the voicemail due to them being so busy. 
I'm 29 weeks pregnant and I have no clue what I can do until I see my doctor next week. 
Please if anybody knows anything let me know.