Any adverse effects on the fetus from oral glucose tolerance test?

My mom was forced to take an oral glucose tolerance test (the results were negative) during her pregnancy with me even though her blood sample was normal. I’ve always had health issues such as lightheadedness, dizziness, blurred vision, fainting episodes, bloody noses, etc. without apparent cause. In spite of these issues, I have always been called healthy. I also have always enjoyed a healthy weight, exercise, and diet. I recently had a test done that came back negative for all sorts of things, such as diabetes and disorders of the thyroid (should have been a relief but wasn’t since no answers). I am concerned that I am not receiving treatment for these issues, I am now a young adult and they are drastically effecting my ability to function as such.

No, absolutely none at all. It was extremely important that she had it because gestational diabetes is very serious, and if she had had it, it would have needed to be treated through the pregnancy to keep YOU safe.
Your health problems are in no way related to that.
Sounds like you need more detailed testing, and possibly get to some specialists. Good luck.