Dry eyes can be caused by tens of medications, in addition to a lot of health conditions.
Please feel free to post here while you are trying to figure out what is wrong with you. I had a terrible time getting diagnosed, as have many people here. The correct diagnosis is needed to get proper treatment.
Just for an idea of how hard it is for many people to get diagnosed with auto immune illnesses, for one example: the average time to a diagnosis of Lupus is five years, which means for a lot of the people it was longer than that.
If you are sick and know it, don't listen to doctors who tell you that you are "just depressed', or you are just a hypochondriac, or anything else that is not true, which many of have encountered on the path to diagnosis.
Keep asking questions, keep reading on the internet, and keep trying to get tested for conditions that you have symptoms of! Eventually the truth will be revealed, the unknown is how long that might take. I remember thinking "it is always darkest before the dawn" when I was beating my head against the brick wall of an unresponsive HMO in my quest to get a correct diagnosis.
One key to getting diagnosed is to evaluate your symptoms the best that you can, as you are doing I think, then try to gain access to the correct specialist to investigate your illness. Then, if one doctor does not respond, or mocks you, or just ignores you such as not doing anything much and then continually saying 'come back in six months", then "come back in six months", then, etc... move on and change doctors. Changing doctors is difficult but necessary in many cases, and a trick to finding good doctors is getting word of mouth referrals from other patients - fancy medical credentials, in my experience, mean nothing.