Sunday blues. You are dreading going to work tomorrow. Is this a valid feeling?
Ask yourself, “Do you want a job?” If you answer yes, you are in effect agreeing that it is worth the commitment of your job to have money that you can use as a tool to do things in your life. Stop complaining about a decision that you have chosen, and realize it is more of a duty you must fulfill as long as you still want to have the job. Nobody is forcing you to go.
As Epictetus wrote, "Do not believe your situation is genuinely bad – no one can make you do that. Is there smoke in the house? If it’s not suffocating, I will stay indoors; if it proves too much, I’ll leave. Always remember – the door is open.”
Apply this concept to your job. Is there so much “smoke” that you cannot stand it any longer? If so, you should make your decision on whether to stay or not and accept your decision. Why suffer dread over a decision you have already made?
Most of the angst around your job likely stems from something simple: you would rather be doing something else right now. See through this childish preference and realize you would likely rather be at your job than not have one, and thus it is absurd to suffer rather than appreciate your situation.