1990 Mazda 626 will not start

I have a 1990 Mazda 626 that I have had for only a few months. Every since I've had it there have been times when I went to start it and nothing happened. I would wiggle to key and it would start.

A few days ago while I was driving the rear light and charge lights came on and the fan started blowing twice as hard as normal. I drove it for a few days with no problems.

Last time I drove it I was gone for about 30 minutes and when I came out it would not start. All the lights worked but no matter what I did it would not start.

I can jump start it but it will die relatively quick after removing the jumper cables. When I measured across the battery posts there was only 12V. Even with the cables in place you could see the voltage diminishing.

It is completely dead now.

I am thinking it is the alternator but I also believe I may have more than one issue.

Any thoughts? Thanks