37F, 130 lbs, experiencing sleep disturbances suddenly out of nowhere

All my life, I never had any problems sleeping and staying asleep at all. If anything, I was always that deep sleeper that would have the hardest time being woken from her sleep.

That all changed about a month ago. I suddenly started waking up around 3 or 4 or 5 AM every single night, regardless of how early or late I fall asleep. I wake up and can’t fall asleep until 7 or 8 AM, and by then, it’s usually too late to fall back asleep, so I go through the day feeling groggy and tired.

No lifestyle changes or anything. So why am I suddenly experiencing sleep disturbances out of the blue? It’s been happening to me every single night for the past month now.