Background info: 22yo, male, no allergies, fit, do exercise with heavy weights 3-4x/wk - have perfect blood pressure etc - overall very healthy

I have suddenly over the course of a few months (starting in August) not been able to get a full night's rest. It has happened all of a sudden and has gotten worse over time. The weird thing is throughout this period I have had a week or two at a time where I sleep normally and feel great. I have not done anything different for those two weeks. But it hasn't lasted. I never had sleep problems before even though I had a less healthy lifestyle than I do now. Also this isn't due to stress or anything like that at all.

What happens is I wake up 3-4 hours after going to sleep then I either can't go back to sleep at all or go back after 3 hours of doing nothing. I do remain calm and don't get anxious but this is just wasting my time.

Timeline of changes to lifestyle:
May 2015 - started lifting after year long hiatus

August - vacation in Mexico (1st night was able to sleep fine but afterward I would wake up in the middle of the night)

September - moved into new apartment for school (since the first night I moved in I had trouble sleeping) I believe it was the temperature at first since I would close the door and it would get too hot so after fiddling with the temperature for a while I got some good nights of sleep but then I would revert back to not sleeping well

December - moved back home for break - same sleeping issues persist

January - move back to apartment and same thing occurs

February - started taking Vitamin D 5k IU, cod liver oil for omega 3, vitamin k2, magnesium (still need to see if I should take it in the morning or night, I took 400mg last night when I woke up at 1AM and I felt really relaxed but could not go to sleep still)

I have looked into things like biphasic sleep but I don't think that applies to me. I was always a straight 8-9 hour person for the first 21 years of my life. Maybe what happened is the temperature causing me to wake up changed my sleeping patterns even though the temperature isn't an issue anymore.

I thought I developed some magnesium deficiency but even with the magnesium I am taking now, while it makes me extremely calm, I never had trouble falling asleep.