Get some rest and look at how things stand when you are in a better state of mind. I find that when i am tired and sleep deprived i tend to be much more pessimistic and doomer about things than when i am well rested. Then you can look at your situation rationally and decide what works, what doesn't and what steps you need to take to fix the issues you are having. Perhaps you will find there are less drastic measures that can reduce your work load somewhat instead of going to the utmost extreme of deciding to give up altogether on something that you have already invested so much in and worked so hard for. That being said if you do at some point decide that what you thought you wanted to do is no longer for you, then that is ok too, as long as you take the time to really think about the decision you are making and ensure that you have good reasons for it and are not acting purely on stress, exhaustion or other negative emotional states.
I can't offer any more concrete advice than that because i don't know the specifics of your situation (which is probably for the best as you shouldn't share too many personal details here anyway for opsec reasons).