I need help

I recently purchased a 1994 Toyota 4 runner with 126000 miles. It is a V-6 automatic and 4 wheel drive. The other day it was real hot outside and I went about 4 miles to come to a sop light. At that point I noticed my car got shakey and felt like it was going to stall. The idle was fluctuating a bit. I continued on another 2 miles or so and it continued to do that when I came to a stop. When I took off she seemed kind of hesitant and then the check engine light came on. Shortly after I noticed the A/C was not blowing cold air. At this point I headed back home and the car started to overheat. I had to pull over 4 times to let the car cool down for a 6 mile haul. When I got it home there was no antifreeze in the radiator or the reserve. Only dried brown substance. Filled it back up and it was very thirsty. I noticed while the car was running a white smoke coming from the exhaust. After putting coolant in the radiator the A/C blows cold again but it still shakes when stopped. The smell of gas or something is present. I am thinking head gaskets but I am female with no experience. Can you please advise me?