Suggest Treatment For Red And Sore Buttock With Bleeding

Im 14 im 5'3 and 116 pounds i dont have any medical history but im a vegaterian for 2 and a half years now. i have realised that all the way up bum crack is verry red and sore and it started to bleed a verry small bit and i have noticed that i have the shakes somethings it can get really bad whats the problem please ?