Struggling really bad.

You can start by getting some exercise to stop the brain fog from getting any worse; if you decide to do cardio, like running, it will actually reduce it as well.

You can choose to sleep an hour or two earlier. It'll prepare you for the next day and mitigate brain fog as well.

You can choose to eat almonds and cashews to replace some of the zinc and other micronutrients you lost during ejaculation.

You can choose to meditate and build up resistance to the next set of urhes you will face.

You can choose to endure a cold shower to reduce the time you spend in depression from this relapse as well as hasten your recovery period, at least as far as dopamine and testosterone production are concerned.

You can choose to go to a public library to study the next time you experience urges.

You can choose to recognize that one relapse does not, cannot and will not ruin 2020 for you unless you allow it to send you into a spiral of relapses.

You can choose to do a lot of things.

 

It sounds like you need to stop worrying so much about the future and think about the present. You seem to have too much on your mind.
Please take some to breath and relax in a quiet environment. There is tons of advice here for how to get more motivated, and you should check some of it out.
The good news is you know you have an addiction and you want to change. Early January is a perfect time to begin working on yourself.

 

From my experience, there are times when I am not strong enough to fight. Sometimes a few weeks, sometimes a few months, sometimes even longer. I don't really know why, at these times it feels impossible to quit, I just don't care enough, and I keep relapsing every few days.

Other times I do feel like I care a lot and I get very motivated, this is the right time for me to start a streak, hopefully longer than the last.
So my advice would be to stop worrying about PMO for a while, and just focus on other healthy things. And when you feel you're ready, get serious and start a new nofap streak.

 

Most people here have gone through these nightmarish phases. I understand your pain. Given the circumstances, the best thing we can do is to keep moving. It is okay. If you keep fighting and if you persist, you can overcome this crap!

Plan out your day...Drink lots of water and listen to the advice of your fellow travellers.

Never give in my friend. You can overcome this. Cheers!