Penguin has pretty much said what I was going to say, but classic anxiety symptom for me when it's at its worst is tingling hands. That's how I know my anxiety/panic is really bad. Plus the heat in my body like Penguin said. Plus being in bed, when you're not distracted, your thoughts and anxiety will increase probably more so than in the day time. I experience that ALOT.
I try to remember that it will pass, its not harmful and is just anxiety. It always passes. I do all my coping techniques like breath work etc. and now on anxiety meds that are helping very much with dampening it down.
I'd say its pretty much going to be your anxiety. It's a common symptom. One I'm very familiar with but it will pass, ebb and flow and nothing to be alarmed about, although I know its not nice to feel. I try to not give it a reaction and say 'it's OK...its just my anxiety...I am safe...it will pass'.
Xxxx