Working out as a full time worker

My bf started working out again last week and im super proud of him. We both said we would start this month. I work in an OR and wake up at 5AM and am constantly moving at work, he works from home. He also has a gym in his complex. I only have a walking pad but it’s in my moms room and she tells me when I can use it. Today I came home ready to work out but my mom said I couldn’t until later. I ended up taking a nap and now im so exhausted. I just wanna go to bed. My bf was pushing me to do it but I just can’t push myself. My body is so tired. I feel really bad and feel like I just can’t get myself to work out ever. Im just always exhausted. Idk how I’ll ever do this while working full time. How do people do it.