Could I be pregnant?

My period was about a week late and was shorter than usual, but nevertheless it still came. I've been really moody experiencing weird mood swings and I've had nausea  for about 2 and a half weeks. I'm in college and I read that stress could cause some of these things. My appetite had increase so I've gained a couple of pounds only two or three but I'm still worried. My boyfriend and I recently stopped using condoms but we've been using the withdrawal method I know it's not 100% effective for pregnancy but we both got tested and decided not to use condoms as much anymore. I know this is a lot but could I be pregnant?