Labor signs?

I am a FTM (33w4d) and just knowing when labor starts concerns me. I have been having constant constipation everyday that I would get nauseous daily because I can’t go even with high fiber diet and increase water intake. So, finally, I think I may have pushed myself too hard yesterday at work (I’m an surgical nurse) working this difficult and long case. I called off today because I can barely walk myself and last night started to start doing number 2 ( not diarrhea but loose enough that I had gone 3 times already since 3am. Also back pain is just on the roof as well. Nothing much other than that, everything else is normal. I guess everyone is different but I don’t know if this is my body getting ready for labor?