Most times, if you are on your period you cannot get pregnant because - without getting to medically technical -everything's getting cleaned out. There's nothing for the egg to attach to. But, if it's at the end of your period, it could be possible because the uterine lining is starting to rebuild & is giving the egg something to attach to (the uterine wall lining becomes the placenta. Every month you shed the old & build a new one). Not all women have 7day long periods, and some can have a regular one that ends abruptly.
You should never have unprotected sex!! Not just because of unintentional pregnancy, but STD's and HIV & AIDS. No guy is worth dying for.
In the end, of you had unprotected sex, you need to have a pregnancy test. But most can't be done until you've missed your following period, and the "pee" tests aren't always 100% accurate.
There is a high possibility of pregnancy in such a case. You can take a pregnancy test to be sure since missing a period point to being pregnant. Go see a doctor to get tested, or you can also do a test on your own using a home kit.
the first couple days of menstruating your safe, then days 3, 4, 5, use a condom,...days 1, 2,, you 90 percent safe,...days 3 and 4 50 percent safe, I never used a condom and the times we got pregnant were days 12 or 13.. Play safely, and be responsible...