I had sex about two or three weeks ago and two days after i did my vagina started to hurt and smell different. And i have no idea whats wrong. And know every night i get up and go to the bathroom at least 2 times and it hurts.. It even hurts when i try to sleep.. Then it will go away and when i least expect it, it starts to hurt again..So please any advice would be good
Yes, go to your doctor and get it checked out as soon as you can.
It could be a vaginal infection or you could have a Urinary Tract Infection, which can also happen after sex. If it is a UTI, in the future, make sure to always urinate immediately after sex to prevent infection.
Also, if you didn't use a condom, you need to next time and every other time you have sex. Unfortunately, it is also possible that this is an STD.