Occasional Phases of Dry Eyes. Plz Help!

Hi,

I am a 22yr old male. Occasionally, I have will have phases of having dry eyes. My eyes will feel dry, gritty and tired and my eyelids will feel heavy. And this usually happens only an hour or so after I wake up no matter how much sleep I get. Whenever, I close my eyes for a minute or so, they'll feel better but will revert to dryness in a minute or less later. These dry eyes phases that I have will usually last 2-3 weeks, afterwards they will fine again. These phases will occur usually once every 3-6 months. So I was wondering, could it be the weather, climate though these phases can occur any season of the year and do not occur more during any particular time of the year. Also these dry eye phases do not occur consistent time interval. They kinda pop out randomly. I was also thinking maybe it's the stress? Or is it something worse?

I've also tried eye drops and eye wash, but do not seem to help. The only way is that it goes away after the phase, but will come back again later on in a couple months or so. Plz help..