It all started with a sore throat 7 days ago . i went to the docs and am on antibiotics. now 2 days later the inside of my mouth is sore as well??

Examination : Is needed of the oral cavity and tonsils. Need to work out whether was a virus that wasn't going to respond to antibiotics or whether you are having a drug reaction to the antibiotics. Needs urgent reassessment

Virus: Very likely that the same virus that gave you a sore throat has also give you some oral ulcers. Did the Dr do a throat swab? The VAST majority of sore throats do not warrant antibiotics.