What can you do with friends like this????

ok so i have these two friend one is a girl and the other is a boy let call the girl Mary and the boy John. so i have know John alittle bit more than Mary. but the problem is that Mary and John dont like each other lk Mary tries to b nice to John all the time n even tris to be firend with him but John on the other hand is lke relly hard to talk to he doesnt lke Mary he always calling Mary old and all sort of other names. these two people are my bestfriend and tomorrow is a field day in our school and i jux cnt hang out with Mary and leave John or hang out with John and leave Mary out am lke really confused and i do not know what to do..i love them both equally but sometimes John can b a dick n I dnt want to choose between my two bff...please anyone help me or give me an advice on what to do b4 i go to school tomorrow am really confused please hlep me oh did i also mention that tomorrow is my birthday n Mary is gonna makes me browine and John want to make Browine also simply bcuz Mary say she will makes me Browine..