itchy down below

Hi. I am a 19 year old girl. I have been dating the same guy for 2 years now and we have unprotected sex but I am on the pill. He was a virgin when we got together and hasn't been with anyone since me and the same for me. Lately since we last got together I have been dealing with an itchy vaginal hole if you may and a little bit of burning when i go to the bathroom and pinkish colour when i whipe. It was painful the first day and now not too much, I have had this for 3 days now but the itching just started today but has happened before. What could be the reason for this. I thought that the burning while urinating is because I try and hold it in sometimes or maybe because I don't urinate directly after intercourse. Please help me out.