Im 16years old, me and my boyfriend have had sex using a condom a few times now. I had my period on the 22nd-25th July so last week and today 31st July we had unprotected Sex, he didn't ejaculate inside me however I'm really paranoid I could be pregnant? :/

Of course you can be pregnant - that's not paranoia, that's the truth.
Didn't ejaculate?? What ever happened to all you learned about sex. You know that doesn't mean anything. Even condoms don't always work. If you don't want to stay home for the next 18 years spending every moment of your time and dime on an offspring, go to a clinic and discuss some less risky BC.

Yes u can still be do a test and find out and use condom or get on to the inplant