22 Weeks - some symptoms ...

I’m finally 22 weeks and although I think my pregnancy has gone rather smoothly I was wondering if other people are feeling these symptoms- backaches that keep you up at night despite medication/heating pads, headaches that persist through medication & keep you awake and last 8-10hours, frequent constipation despite fairly good diet, daily walks of 20mins or more and lots of fluid & weight gain fluctuating due to fluid build up as much as 5Ibs from one day to the next. I have my doctors appointment this week- but was hoping to get some advice from anyone else that has experienced this. I just want to sleep through the night, reduce the headaches especially and figure out my digestive system/fluids. Thanks in advance for any tips/suggestions!