Braxton Hicks?

I think I’m having braxton Hicks. I’m 30 weeks but I’m not sure if that’s what they are. My stomach is tightening and getting really hard for 45 ish seconds but I’m also finding it very uncomfortable and hard to breath almost. Is this normal for braxton Hicks or could it be something else? Ftm here and never had them before so I just want to make sure that’s what I’m experiencing.