FYI I'm 17y/o, 5'11, 150lb.

I've started becoming more dedicated to building muscle and I'm going for a moderately intensive programme, 4 days a week (plus martial arts training once a week). I'm mostly focused on the big three compound lifts, plus strengthening my core.

One problem is that I really struggle to go a day without doing some kind of exercise, I'd even go as far to say it causes me anxiety not to. What is some efficient exercise that I can do on those days where I don't have gym access? I'm thinking some kind of bodyweight/calisthenics routine or just cardio.