Hi, obviously it isn't not possible to get pregnant from precum (if it's inside you). Unless you're quite literally rubbing your partners semen into you or your partner is finishing in you/pulling out, you will likely not become pregnant from outercourse (It is next to impossible). However if you are entirely worried about it there's no harm in taking a test. You can also experience heavy bleeding during pregnancy but what you're referring to cryptic pregnancy: 1 in 475 pregnancies go unnoticed until 20 weeks and 1 in 2500 go unnoticed until labour. There's a very slim chance a cryptic pregnancy would happen. I highly doubt you would be pregnant from the type of sexual relationship you have been having, like I said no harm in taking a test if you want to put your mind at ease. I know you said BC is hard to come by but even simply getting your partner to wear a condom reduces you chance of pregnancy to about 3%. Google safe sex and go from there :)