Feel like my baby's coming early

I've been getting lightening crotch for like a week or two now. More contractions. And nesting like crazy... everyone thinks she's gonna come in the next three weeks!! I just wish I knew for sure.
 Haven't had an ultrasound (that was more than a few minutes) since 23 weeks so idk how big she is... Hoping she holds on to at least 34-35 weeks. But I'm getting such bad back pain tonight who knows😩 Anyone else feel like their baby is coming early..I'm 33 weeks right now