What's wrong with my car? Overheating and no A/C?

A few months back my air conditioning broke, which I was okay with. We get really hot summers, but I couldn’t afford to pay for repairs, so I just dealt with it with the windows down. But then my car started overheating while driving home from work. The red thermostat light came on and started blinking. I took it in and it was fixed, or so I thought. The AC was working again, for a few weeks. Then it shut off again, and only blows hot air. Now the over heating thing is happening again! Any ideas what might be causing this? It’s a 2001 VW Beetle, automatic. (It was a hand-me down, I didn’t pick it out, and yes, it still has a vase in it.)

And an added note, the AC worked sometimes for short periods of time. It seemed to kinda be on and off, but once it went off for a while, it pretty much stayed off. A friend asked me if it seemed to not work on hot days, and work on cooler ones, and I don’t know if that info helps, but either way I think that might be the case, I’m not sure. It could have been coincidence too…