Getting angry at my lack of motivation

The best kind of motivation is the kind you give yourself. It really comes down to your own desires and decisions you make based off them. Do you desire to live a healthy, happy life, more than you desire to be lazy and look at porn? Then start making the necessary decisions that will you lead you in that direction.
Not sure what your daily routine is like, but start taking small steps, commit to one habit at a time. Pick one thing, whether it be going for a mile jog every day, meditation in the morning, no social media or technology past 8pm, etc. Start with one thing like that and stick with it. Pretty soon it will become habit and you won't even have to think about it.
Becoming motivated and working towards a better YOU isn't something that will happen naturally. You won't "feel" or always "want" to make the right choices. What's important to realize is you have to look past your feelings and step outside of your comfort zone.
Do you have a job, do you work?
Find something productive to do and stick with it. Start with one or two good habits and keep at it. Porn addiction thrives in boredom and secrecy. The more time you spend thinking about how messed up your life is, how much damage your PMO addiction has caused, how weak or lazy you are, how there's nothing to do, etc., the more things like PMO will have a control over you.
It's all a mindgame. You have to push aside the negative thoughts, look forward, and start taking small steps in that direction.
Also, get out more and socialize a little bit. I don't know your living situation of how many friends you have... but I think socializing with others is important for our mental health. I wouldn't go as far to say make it a priority or anything, but I think simple discussions or hanging out with others or whatever helps us develop care for others and helps get our thoughts off of ourselves all the time

 

The overuse of the neural pathways after PMO causes a downtick in the number of dopamine receptors, hence the lack of motivation. I think you may need to set up your environment in a way that will increases your chances of success and reaching your fitness goals. Start small, like exercise for 5 minutes. Then up it to 10 minutes. Then 15 minutes. So on and so forth. Make the baseline goal so easy that you will achieve it with minimal effort. Build up that habit first. Even if you exercise for 5 minutes a day, that's 35 minutes a week. Do that for a few weeks. It's better than nothing. If you can build up these habits then you don't have to solely rely on motivation. Remember, that you're not going to feel motivated every single day, especially if you are rebooting. The brain takes time to regain sensitivity and normal functioning. Exercise actually boosts dopamine in the brain and instead of focusing how you're not feeling motivated rather you should think about how good you'll feel once you're done exercising. Write down what are the things you want to do and stack the habits that will get you one step closer to the goal. I recently read Atomic Habits and there was really good advice in there that you may find useful.

Cut the chord of PMO and allow yourself time and space to heal. Don't rush it. Don't focus so much on the goal. Enjoy the process and stay in the moment. Take it one day at a time and you'll get there eventually. But it's predicated on committing to yourself and to your self-improvement. One day at a time. The more you do things that you know you should be doing, the more you will reinforce to yourself that you're a go-getter. It all starts with a single step; just do it. You know you can.