Butt pressure?

Im a ftm and the last few hours ive been having a lot of pressure in my butt area and pelvic area. I feel like I constantly have to pee and im feeling really gassy but only when I stand otherwise its just pressure (for the gas that is). I'm only 35.3 weeks and I'm not having contractions so I'm hoping its not a sign of pre term labor. My daughter is definitely really low though. Should I be worried about the pressure or is this just a normal annoying symptom?