My 01 Buick regal begins to overheat but then usually goes back to normal.

What is your question?

My car overheats but then usually goes back to normal. Today my car overheated and went all the way into the red. It went down a little after turning the heat on but never made it back to normal and just kept going back and forth from overheat to about 3/4 on the gauge. Not really sure what the problem is. Any help would be great. Thanks