Why waking up at 5 am anxious?

Hey all,

While I am sleeping much better than I was a year ago, every single night I wake up in the middle of it.

I usually wake up after about 5 hours of sleep, so if I go to sleep at 2 I wake up at 7 or 8, if I go to sleep at 11 I wake up at 4 or 5 etc.

I wake up with intense heart palpitations (this is an ongoing symptom for me related to GERD/digestive issues), and anxiety.

If I wait about an hour and read it usually goes away on its own and I fall back asleep for another 2 or 3 hours and sleep really hard.

Why is this? I've heard about liver issues doing this? cortisol? I am stumped.

FYI I am working on candida and adrenal fatigue, with significant but not complete improvement in both areas.