I Am Having Tonsilities For Which I Am Taking Penicillin.

I am having tonsilities for which I am taking penicillin. Apart from tonsilities I even have cough and bit of mucus formation for which I was prescribed benadryl. But problem now is benadyrl is caused my stomach to be upset and I cant take much liquids like milk , solids I can eat because of tonsilities so that also I have to avoid. Just want to check what food can I take also how long does it takes for fever to settle its been more than 4 days now and I have constant fever of 41.C?