Work will always be there. Thesis won't. Talk to boss and thesis supervisor. Tell them exactly what's going on and that you need support for the next [x] weeks. Ask for an extension of deadline. Work less hours and cut living costs for 2-3 months. You have more agency than you think you do. Steel yourself and make the calls / send the emails. I get you're absolutely tired but this can literally all be over by Xmas (or jan, with extension) if you ask for help now