Vagina sore and itchy after sex?

So I had sex with my girlfriend last week (I'm a girl, might I add) in the shower and she put two fingers in me, although I had to stop because it hurt. This is only the second time I've had sex in my life. We thought I was wet enough and I guess not, I was too dry. The next day my vagina swelled up and became really sore and itchy. It's nearly a week later and, although it has gotten slightly better, it still really, really hurts. I've used Vaseline on it which helps for a short while before it gets bad again. Paracetamol helps too but I don't want to take too much of it as it ends up losing its effect whilst I really need it. So has anyone got any tips to keep the soreness and itchiness at bay? It probably would have gone by now if I didn't stop itching and rubbing it but I can't help it! So yeah, tips would be greatly appreciated, purely because it's becoming unbearable to sit still in class and I miss using the exercise bike at the gym! I'm hoping a good bath will help it when I go home this weekend...