Help FTM

Since I was 27 weeks I started noticing my belly get really hard around my belly button area.. It would last a good minute & then go down I told my doctor & she said it was just the baby moving. I'm now 34 weeks & feel the same thing just stronger & they actually are a bit painful. It's bareable just uncomfortable. I've also been experiencing REALLY TERRIBLE UNBAREABLE back pain these past couple of nights.. Is this something to worry about? I have also been super super tired lately where I don't even want to get out of the bed or the apt.. I can get the most sleep & still feel really tired the next day