If you're using protection correctly then it's unlikely (not impossible) that she's pregnant but I would try not to worry about abortions etc until you know for sure whether or not she is pregnant.
If she is late for her period then take a test. Stress can affect the cycle so missing a period isn't an automatic sign of pregnancy but the only way to know/put your mind at ease is by getting her to test. If it's negative and she still doesn't get her period then test again after a few days. It may well get her down but taking a test isn't going to change the reality of the situation (whether she is or isn't pregnant) and you could well be worrying uneccessarily.
As for abortions I am in the UK (and have had a surgical abortion). If you're wanting to go privately (as I did) for an abortion then the cost will depend on the clinic you use (BPAS or Marie Stopes are the main ones) and the gestation of the pregnancy. It's around £60 for the consulation and about £600 for a surgical abortion in the first trimester. I imagine that medical abortions are a similar price but you would have to check with the provider.
However, abortion is available on the NHS if you were unable to fund it privately . To access this she would need to have her GP confirm the pregnancy and be referred from there to a hospital or clinic.
My abortion was under general anaesthetic so the procedure didn't hurt, although it was uncomfortable following.
Try not to worry though, exlplain to her it's unlikely but that you do need to know/she does need to test.
Best of luck