Differentiate: Signs and Symptoms of Pregnancy and Periods.?

There are a lot of signs and symptoms of pregnancy and periods, that are the same. I have been looking at the answers that most people say about the signs and symptoms of pregnancy and periods, and I'm really getting nervous.

Me and my boyfriend had sex on the day of my last period. I counted the days that the symptoms of pregnancy would surfaced, and the exact day of my period, if it is normal (They say that most women have they're regular periods when you are already 18 years old and above, am only 17, so am irregular), so I could keep track of it! If I am pregnant my period will not come within that 2 months, but if within that 2 months I had my period, am not pregnant, but osme answers that were given say that even if there is bleeding there is still a possibility of being pregnant, so I looked at the signs and symptoms, but most of them are the same, except for the vommiting part, but other than that its still the same.

So can someone please help me?
Immediately!!!!

Buy a pregnancy test. That will tell you if you are or not.

buy an early pregnancy test, and next time if ur not pregnant, use protection if u dont want a kid, or keep ya legs shut, easy as that, i had my son when i was 17, pregnant when i was 16, i love it, but its ***** hard, even with his dad here, my boy makes me so stressed n mad sometimes that i cry, and another badis,u get fat, n u get wrinkles, im 19 and i have wrinkles andmy body is destroyed, but i love my son and wouldnt change it for the world, he is the best choice i have made ever, but it is really hard, u always struggle for money too when ur a young mum, and everyone seems to be against you, they stereotype you into a bad category ofppl n treat u like crap