Struggling to Start My Fitness Journey – Need Some Advice, Insha'Allah

Assalamu Alaikum, brothers and sisters. I'm a young man who's very underweight (5'7, 94 lbs) and fragile. I've been wanting to start going to the gym to build strength and health. But lately, whenever it's gym day, I just don't go. Sometimes I can't wake up because it's cold and I hide under my blanket, or I tell myself it's too early or dark to get up. Today, I tried leaving my phone below my bunk bed so I would have to get up to turn off the alarm. I did get up, but my mind was foggy. I had 8 hours of sleep, the door was right there, and I could have brushed my teeth and gone to the gym for the first time. But I hadn’t watched the exercise videos properly, so I worried about hurting myself doing the exercises wrong, especially with my weak body. I stood there for about 10 seconds trying to decide if I was ready enough. In the end, I went back to bed because I felt so tired, like I didn’t have the energy. Also, I think part of me feels like doing anything beyond staying home and resting is unnecessary – maybe because of how sheltered I was growing up. My parents used to say I'm too sheltered, but Alhamdulillah, I’ve moved into a college dorm now so I have more freedom. I woke up an hour later feeling regret because I really want to build the body I dream of. Being so skinny and fragile has caused me pain and shame. Someone once told me if I avoid this, maybe I don't want it badly enough. Maybe that's true, but I still hurt being this way. I want to start and keep going, Insha'Allah. If anyone has advice or encouragement, I’d be very grateful. Jazakum Allahu Khairan.