I had sex two weeks ago and my partner came early and rubbed his penis on my vagina; could i be pregnant?

Unlikely: It depends how many (if any) sperm got inside your vagina. Certainly it is possible albeit not likely. If you are very concerned get a pregnancy test, particularly if your period is late. In the future i recommend using condoms and/or some other form of birth control for sex. Condoms will also reduce your risk of getting a sexually transmitted infection.