For some reason when I accidentally tried to upgrade my gallery, it didn't tell me I didn't have enough TU  on hand, so I thought okay weird but let me take TU out and see if that fixes it, and now it just says negative that amount. How do I fix it?

you just pay it back, so it'll take money off you no matter if you have it or not, the only way to fix it is to pay money back to your hand and put it in positive again :) good luck