sick and new

Hi I was diagnosed with lymphoma stage 2 hodskins at age 16 December 1st I was just had my second large dose of chemo on the 5th but after getting my normal weekly chemo I started to notice that every time I ate it felt as if my stomach was pure raw. Also It wouldn't even be more then a minuet and my food would come back up. I have thresh and that won't seem to go away.I think I have mouth sores but I'm so inexperienced that idk what to look for.I brush my teeth daily and use marrys magic mouth rinse or a medicated mouth wash filled with stuff to numb my mouth and to help fight bacteria. I'm on prednisone,pepcid (2x daily )senna and many more. But my pepcid isn't even working I'm vegetarian. I only eat Ramon noodles and anything creamy and easy to eat I also take melitonin but get back up at 4 am and it's getting worse I am up all day and night