I need help with being a diabetic?

i am new to being a diabetic, my dr just started me on meds friday, I am a 2 diabetic and my lvls keep jumping all over the place one min after eatting it went to 374. then it goes down to 331, then it jumps back up, I honestly don't know what kinda food to eat This is what i had today so far will some one please help me understand, 2 pieces of low butterd when bread toasted and a boiled egg, for a snack i had 5 peanut butter n cheese crackers and for lunch I had 2 tuna fish n mayo n cheese sanwiches I don't want to do any more damage to my body, what can i do to get my lvls down when they spike up, If I i was to get up and be active would they drop down? some one please help i am so confused!