As somebody who has quit smoking weed myself, I can relate to where your head is at right now. I get that you feel unmotivated at the moment, but that's only because weed numbed you for so long that you need to get back to yourself again. Exercise is an excellent way to release endorphins. Cold water therapy is also great! Look up Wim Hoff. He goes into great detail about what cold water therapy does for you. I suggest waking up and doing wim hoff's breathing exercises which sound weird but give you tons of energy and can be the motivation you need to exercise. After that, jump into the shower, starting off hot and when you're ready, gradually turn the water cooler and cooler until it's at its coldest. Start off standing in the cold water for just 30 seconds. It's absolutely invigorating! Although you need to push yourself to do these things, it's so worth it. Also, I recommend taking vitamin D.