Did he do a Schirmer's test for dryness? It is actually quite normal for excessive tearing to occur with dryness. The feeling of foreign objects/grit in your eyes is tell-tale dryness and/or inflammation. A Schirmer's test is a little strip placed in the eye to determine tear production.

If you continue to have odd sensations with your eyes, i would suggest seeing an ophthalmologist vs optometrist. There are numerous tests to look for inflammation, etc. that an optometrist might not catch.