ADVICE PLEASE 18 weeks 6 days !! Pregnant

This is my  third pregnacey and the furthest I've been in any of my pregnacey a. I am new to all of this pressure and Feels like my uterus is pushing on my bladder a lot lately hurts to sit down.  Hurts to lay certain way  lots of pressure. Feel like I am gunna explode could I be poppin soon I know about now our uterus  is about the size of a cantaloupe  so it's not a huge suprise  about the pressure just really hurts. And Tylenol dosnt help  very long and heat packs. Help for a little while. But don't wanna over heat baby. Any suggestions  on what I can do my ultra sound is in 13 days so hopfully  everything will