Whenever going to sleep knowing I want to WBTB or even during a WBTB when I want to WILD it is harder than trying to fall asleep without any goal.

Last night for me was a perfect example of this problem.
I am planning to attempt FILD each day this week. Yesterday was the first. I went to bed at 9:30, which is early, just because I had a feeling I would have this problem. I resisted the temptation to check the time so I don't know how long it took but it was definitely over an hour of me trying to fall asleep. And then I woke up at 12:30 naturally, and it took around 20 minutes for me to get back to sleep. And then I woke up naturally AGAIN at 3:30, and it took another 20 minutes to fall back asleep. IT DIDN'T END, I woke up again at an unknown time, I decided to just try rest a bit and try my attempt then, because surely I had gotten enough sleep. So I was attempting the technique when my WBTB alarm went off, and at that point I gave up, and it took around 10 minutes to fall back asleep.

I'm sure a big problem is just thinking about what is going wrong and getting angered over it, but it's hard to control these thoughts. I feel even if I tried a relaxation technique it would go to waste because right after it I would start worrying again. This is a mental problem rather than physical. How can I just empty my mind.

Also I have one more problem. When attempting techniques like this I often get nervous and heat up, how can I help this?