Dizziness, lightheadedness - new med side effects?

Hi all, for the last week or so I have noticed that I have become light headed and often dizzy. I've been increasingly tired each day despite going to bed earlier and getting at least 9 hours' sleep. I feel kind of a buzzing tiredness in my head and my eyes are tired and dry, feeling like they're burning.

As usual I was anxious that I might be serious ill etc, but there are a few things that have changed in the last week or so which might be to blame:

I've cut down a lot on caffeine, I missed a couple of doses of cit because I've been feeling so good I just didn't even think about it, and I've got a new laptop which might be hurting my eyes, but I have also started taking omeprazole 20mg for a suspected stomach ulcer, and all this started a few days after I went onto that.

Has anyone else had problems with antacid meds?