Painful cramps at almost 13 weeks. 😕

I had an ultrasound at 8 weeks that showed a healthy baby with a heartbeat of 180, heard the heartbeat at my last appointment and my doctor said everything looks great. I've been having painful cramps for the past week though, no bleeding/spotting. Is this normal? From what I read it's probably my uterus stretching but is it supposed to be very painful? I'm a first time mom so every little ache and pain scares me so much. Just looking for some reassurance, I guess lol. 💕