I'm sorry, but you don't even sound old enough to be having sex period. First off - look into getting on the pill, or some kind of birth control. You shouldn't have to come online and ask total strangers if you can get pregnant just from your boyfriend rubbing on your clothes.
To answer your question, though - it is very unlikely that you're pregnant. If he came in his undershorts and not on you, it's near impossible. Even if he were to do it on your outer clothing, sperm can only get through certain types of cloth, let alone what it would take for it to get to your area AND inside.
I don't know how old you are or how long you've had your period....but if you're young and haven't had it long, it's most likely due to that.
I know you said women only.. but I had to give ya some input!
As you see with the answers, EVERY woman has a different perception of how a guy should dress. I would consider myself to be a well-dressed fella.
First of all, you always have to dress with what your age group represents. I'm 23.
The best way to dress is to keep it simple. Make sure you get well fitted jeans (but not too skinny and never baggy). White jeans are okay to wear in the summer, but never for the winter. ALWAYS buy dark pair of jeans. Levi's has the best. And you can mix for example, good-fitted (slim jeans) with air jordans/vans, dark jeans, and get plenty of plaid shirts (H&M, Pac Sun & Zara r the best).
Get some plain tee's too. Plenty of black, white, gray.. but make sure they fit you well.
And yes women do look at shoes! your shoe defines you. So if you wear air jordans, you'll attract more athletic women. If you wear converses you'll attract hipster girls. Dress shoes = mature ppl. etc.