Am I feeling braxton hicks or something else?

Amber • 20 years old, mumma to my beautiful boy Oliver and expecting my second in Jan 2018 👶🏼
I'm 36+5 weeks and I haven't felt any practice contractions yet but tonight baby feels really heavy on my bladder and it feels like I have really bad period pains. The pain is constant not stop start and walking around and moving from standing to sitting and vice versa is really uncomfortable. Is this normal? I'm really struggling to move now, i don't think baby has dropped yet but then again I wouldn't know if he has it not since this is my first pregnancy so I'm a bit clueless