Dear hambo,
unfortunately condoms do not give you 100% protection. Your girlfriend really needs to be on birth control pills or some other form of contraception that is more reliable. Condoms are ok for protecting yourself from sexually transmitted diseases, but I would not rely on it as your only protection from an unwanted pregnancy. If your girlfriend is 10 days late on her period, then yes it is possible you have used a condom that has failed, it may have split or had a hole in it, and she may be pregnant. However you did mention it is not unusual for her to be irregular, therefore it may just be that, a late period. She is only 16 and teenagers hormones are still adjusting themselves, some women don't have regular periods until they are in their 20's. Birth control pills would actually keep her periods regular aswell as protect her from becoming pregnant, they are 97 - 99.9% reliable. A much better percentage than condoms. Not all women get symptoms in early pregnancy, but the most common symtpoms are usually frequent urination, sore or tender breasts, sensitive nipples and nausea. You will need to take your girlfriend to get a pregnancy test which you can buy from the supermarket or chemist. Otherwise there may a clinic close by who offers free pregnancy tests. Either way you need to be sure she is actually pregnant before you worry yourselves to death. As for an abortion without her parents knowledge, it really depends on the laws in your state, but i'm sure there are places that could help you if you were to decide on an abortion. Have you given any thought to the possibility of maybe keeping a baby and raising it as a family ? I know you mentioned that your girlfriends parents would freak and never let you see her again, but maybe they wouldn't freak. They may be upset at first but i'm sure they would come round after they realise the child needs it's father, and i'm sure they would want to be close to their grandchild. Anyway, both you and your girlfriend have a lot to think about, and a very big decision to make. If it turns out she is not pregnant, please try to convince her that she needs to be on birth control of some kind, her doctor would be happy to talk to her and discuss contraception options to suit her needs.
Good luck,
.::suzy::.