One-sided pain definitely give your doc a call hon x
Very good chance that's just the side you ovulated from, but let them make the call as to how you should proceed. I had severe left-sided pain at 5 weeks during this pregnancy, they rushed me in for an ultrasound and saw that I had a huge corpus luteum cyst on the left, leftover from ovulation, and that was causing all the pain. It's too early in your pregnancy to see a sac or anything, but it's definitely something to bring to the attention of your doctor because they may want to do an ultrasound anyway.