Have you started using a different washing powder / liquid as rhat could be the cause. If not,
are you using a new shower gel or body moisturiser ? Anything new putting on your skin before bed?
Check your mattress and if you can sleep somewhere else - on another bed or if you can’t on the sofa to check if the same thing happens.
If you are still sweating try sleeping wearing something different too or if you can go to sleep naked too.
All to help a process of deduction.
In addition in your notes app on your phone or on a pad etc, when you wake up sweating write down every feeling you have. Are you thirsty? Do you feel light headed? Do you feel dizzy? Do you feel tired? Is your skin hot and if so: where exactly? Does your throat hurt? Write everything down.
Note down what you ate, what time you ate it too. Log all of the feelings no matter how small for a couple of weeks, each day.
you could also for the two weeks -
Have a shower not a bath before bed.
Dont eat anything after 6pm for two weeks.
cut out sugary drinks / coffee / tea after 6pm.
drink a lot of water during the day.
See your GP and tell them all the symptoms. Get your blood tested at very least for hormonal health, thyroid health, liver and kidney health, heart health. Get your heart rate, lung capacity checked too.
You may have an allergy to your pjs or a new skin product, or one you’ve been using you can get an allergy out of nowhere out of the blue. Your mattress may be cause of sweating. You may have sleep apnea. Your blood tests may show something or not. But until run a process of elimination - you won’t know. Am sure it’s something simple.