Haven't had a bowel movement in like a week, prob due to insomnia, poor diet, dehydration, inactivity, can constipation cause pain right above buttocks?

Yes, I think so.: It sounds like you've been having a very difficult time recently. I hope it is an unusual thing, but even so. This needs to be taken as a serious warning to you about doing every thing you can - perhaps especially in troubled times - to eat well, stay hydrated, get as much rest and activity as possible, etc. So that your body is going to help you through the rough stuff instead of adding to it.