I feel your pain. I'm much younger at 28 and was at my previous "career" for 4-1/2 years right out of college. I knew on the first day of the job I wasn't going to enjoy it, thought I'd give it 2 years to see how it really was. 2 turned into 3 and 3 into 4….. I'm happier now than I can remember and I know whatever happens I'm NEVER going to regret my choice to quit that god awful, soul sucking hell hole. If you have anywhere near $500,000 I'd pull the plug tomorrow.
If you want a letter of resignation I can send you a template