Hi Uniquorn - not a stupid question at all. It sounds like your oestrogen levels have dropped quite considerably and you're now getting classic meno symptoms. I don't think you're using any form of oestrogen hrt as you didn't mention it, but you might like to consider that now. The chin and jawline spots are always an indication to me that my testosterone/oestrogen balance is out of whack, ie. your oestrogen has dropped and your testosterone level isn't being balanced by it. The Mirena progestin is also testosterone based and so it's a bit of a double whammy ie. spots and usually more hair on the face. The night sweats are also pretty classic low e symptoms.
You could ask your GP for a sex hormone blood test but these aren't always terribly accurate, saying that, if your E levels are very low, you'll know on the test. The only other option is to ask your doc for low dose oestrogen hrt. Once you start using it, if the symptoms disappear, you've cracked it, if they don't, you might have to increase dose.
The great thing in your case, is that with a Mirena you can add oestrogen and increase until you get your sweet spot without any worry as your Mirena is protecting your womb nicely.
Keep posting if you're confused, it can be a bit of a head mess this meno business.