1999 Subaru Outback Lots of stuff wrong with my car, but is

Electrical problem
1999 Subaru Outback All Wheel Drive Automatic 175000 miles

I have a 99 Outback wagon with approx 175k miles on it, and my alternator just died, but it's in the shop being replaced right now. But, for many months now my speedometer barely ever works, like it will jump up to my speed but then drop down to nothing even when I'm at full speed. And, I have a headlight out. Could this all be related? Or if its not that easy to say, what might cause my speedometer to not work when everything else seems fine? Thanks so much, you guys have helped me many times in the past.