Advice please!

I'm 5 weeks today, but for the past few days I've been experiencing a sharp pain on my lower right side of my pelvis. It's not constant, but it woke me last night coz it was so painful. It's been coming and going periodically, and isn't getting any worse, but I'm wondering if anyone else has experienced this? I haven't had any bleeding/spotting, but I did do another hpt which I thought would have showed 3+ weeks today on the weeks indicator, but it still says 2-3 (the same as it did last Sunday), should I be worried?