Start packing hospital bag? Car seat?

So yesterday I had a cramp feeling in my stomach that hurt for about 30 minutes I tried moving walking etc it wouldn't go away it also felt like I needed to poo, today in the car I got an off guard uncomfortable pain it stayed for 10 minutes. I'm 34 weeks and have not packed a single hospital bag I've been waiting to get small essentials like travel size items to pack and still need baby hats and mittens, should I just pack clothes for now and keep them in the car anyway & when I get the rest put them in the bag as I go? I like to pack everything at once so I can double check and organize correctly but am scared I might need to go to the hospital and won't have anything at all ! Also should we set up the car seat now? It's a stroller and car seat combo still in box I just figure when baby comes we can rip open the box then?