So much for my singing career?

Now that I'm out of neck brace I've been driving again thank goodness.  Something I'd not anticipated was how much I missed solo radio karaoke in the car.  Although my commute is pretty short, I've been making the most of it and belting em out.  Unfortunately, I've noticed my singing (average to poor at best) seems to have suffered.  I just can't hit those high notes like I used to.  Seriously, I actually can't sing very loudly anymore.  No big deal of course but just a little oddity.  We'll see if it gets better.  I also can't really yell very effectively but I can't find any practical application for that.