Parasite clear is an extremely strong drug that will dose your betta into a slightly intoxicated state. Those are regular symptoms that occur when you use it.
Let it run its course, and your betta should come back. Doing too many things at once makes it very difficult to track differences in what is going on, and no treatment is ever 100% effective immediately.
Keep the heat up to 78 farhenheit, and no more than 82 farhenheit. I keep my tank at 80 at all times.
Your fish will come back, as long as you are patient with it. It will also in turn become very hearty, as you stay patient withit.