Overheat

I took my Impreza out this morning. Some of the stuff I drove through was grass and some was mud. All of it was flat. Afterwards when I parked I noticed my engine was hotter than usual. I thought this was ok because I had been driving it hard. I cleaned off the radiator and started to drive home. I noticed the engine was getting hot. I stopped and saw the antifreeze overflow was near empty. I washed the car and got the radiator good and I think I cleaned the undercarriage well. I filled up the antifreeze and sprayed water on the engine. The antifreeze dropped to between the hot and cool level. The oil level was fine. I thought all was well because the heat stayed at the normal level for a while. After maybe 15 miles it started getting warmer again, but not as warm. I rode with the heat on high the rest of the way home and it got warm towards home but stayed good overall. Do I need to clean something else? Is there something I need to do? Did I hurt my car? Help, TIA.