How to regain Vocal Range?!

[TheComposer]

Give it time and definitely, practice more than 2 days (Specially if those 2 days you spend a looot of time singing), your voice will sound funny, but eventually you'll control it, example, Michael Jackson!! He lost a great range of notes during his teens, but he made it and sang really great, 2 cents.

[Highbone]

The rest of these "preds" are working on angles. Write the song in the key you wanna sing... this is homerecording, no homo, less homie. Just a pale comparision of what IT WAS......

[Radar]

With out us actually hearing and observing you sing it's going to be hard to diagnose your issues on a written forum. Getting a little coaching help, as well as warming up properly, and singing some everyday will all help. I know as I age (I'm in my 50s) I have to work at singing quite a bit to not lose power and range. The teen years can be tricky also as the voice box develops into it's adult state. All of these issues can be addressed by a competent vocal coach.