Could I possibly be pregnant?

I'm 15, I have NEVER had sex, but I used a friends lube for masterbation and it may have had sperm in it, I've gotten all my periods since then but I get fluttering in my stomach and I just feel like I could be pregnant and I'm super scared, could you maybe tell me some symptoms of being 2 months preganant and do you think I'm pregnant, I'm super scared.