Odd symptoms starting at 27 weeks

Sophie
Hi all mommies! Our babies are coming along nicely I hope everyone is getting prepared! I wanna ask if anyone has started getting symptoms out of the usual around late 20 weeks. I went swimming and walked really far a few days ago and the next day I was in so much pain I couldn't walk. Yesterday I worked from 9-7, teaching classes one upon the next. During my break time the baby kicked and I let my co worker feel and then suddenly it was a sharp stabbing pain. By the last two hours I started to feel nauseous. And I went to bed at like 9. Now I'm lying in bed waking up. It's around 8 now and I started to suddenly feel dizzy and nauseous. During the night when I got up to pee I also had much more severe pelvic pain than usual. I never had the nasty pregnancy symptoms in the beginning like most women. I'm wondering if this is all normal or should I be concerned? I passed my glucose test earlier this week and all other blood work came back normal except the thyroid test. Apparently my thyroxine level should be 3.1 and it was 3.6. I have no idea what that even means the doctor just said to drink more fluid. 
Anyway. Just wondering I any July moms are having weirder than usual symptoms this far along. 
Today is another horrible work day with classes from 1-7 without so much as bathroom break. I said that I was gonna try work till mid june but now I see a bleak future even for May. 
Have a blessed Sunday everyone!