Magnesium glycinate issues: Gave me Insomnia!

Hi, new to this community, but I have a few questions/comments and I'm just wondering if I am alone in my situation. Last year, I was taking magnesium glycinate (with doctor's approval), usually only 100 mg and right before bedtime. It worked great for a while, then I noticed that it wasn't quite doing the job - I would wake up after an hour or two. I tried a different brand and used a powder, so that I could take a little more than 100 mg at night. It worked not so well - the magnesium clumped very badly when I mixed it with water, and I had to stop anyway because I ended up with constipation. I gave up on magnesium until a little over a month ago. I tried magnesium glycinate again, 100 mg at night, and again, it worked very well for about 5-6 nights - I slept through the night, or fell asleep not long after waking up once. However, that was short-lived. I started to wake up after taking the magnesium (still 100 mg) - felt calm and collected, just could not sleep anymore. In desperation, after several hours, I would take Benadryl. I also tried taking the magnesium in the morning and/or the afternoon, but I just felt either calm and sleepy or way, way too energized. I gave up on the magnesium glycinate and then decided to try Magnesium citrate (Natural Vitality Calm) using the minimum recommended amount. Oh no, it gave me a throbbing headache in the morning and a little too much laxative effect, and I fell asleep for maybe an hour, then woke up anyway.
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So, am I alone here with magnesium glycinate actually giving me insomnia? I did read online that some people get energized, not relaxed when taking it, because of the glycinate. I might also be affected because it could have a reaction with GERD medicines (my only prescription med is pantoprazole.) Also, it looks like both forms of magnesium get me to sleep, but after a few nights, I go to sleep for an hour or so, then I'm wide awake!

For now, I think I will just try to get magnesium from food alone.

I have also tried melatonin (less than 1 mg) and it gave me a bad hangover during the daytime hours. Also got me to sleep, but up after a few hours anyway. 🙁

And the search for decent, good sleep continues...