You might be able to lift weights when you are more stable. I am able to take ballet classes. Of course I am nothing like what I used to be but I still find joy in doing what I can do. Some days are better than others and I have to take extra mestinon to make it through a class. Lifting weights might be a little more dangerous but maybe you don't have to totally give it up. Like if you use the Hoist machine where there is no danger of dropping it on your head. Don't give up if you love It. You can make it work (but wait till you're on a stable dose of mestinon)