*Beginner* Singing tips? Please be kind and constructive :)

Also just to let you know, when I was doing this cover I was literally so out of breath I have no idea why (I do have asthma but it only really comes up when I’m doing cardio). If someone could let me know anything about breath control and tips for that that would be crazy because I get so out of breath singing sometimes. Secondly I feel like there’s something off about my voice I just can’t pinpoint it, like my voice just sounds so strange to me. Thirdly, I was singing a little quieter because I live in a student apartment with neighbors and I didn’t want to disturb them!