Overheating & Lacking Sleep Past Few Nights

Idk if it's caused by using Systane Ultra just before bedtime coincidentally for the last few nights that I only got 6.5 hours, or if it's something more serious like a thyroid issue (according to ChatGPT and Meta AI). Only my arms, legs, hands, and feet would overheat whereas my chest, stomach, back, and shoulders under the blanket would not. If I continue to struggle with sleeping issues, I may have to consider going to the hospital again to get checked.