Anyone had to retake the test 3 times?

When I was at 28w I took the first 3h test and passed normally. However, when I went to my appointment my weight gain was higher than the other months, so my doctor told me to repeat the test at 33w. I repeated it, my fastening level was normal, but I failed the following by a few points. Took him the results and he told me to repeat the glucose test again at 36w. I don’t get it. Does this make any sense at all? Is the test taken at 33w reliable to diagnose GD? Does taking it multiple times make any difference at all? I can’t stand doing it once again, it makes me feel terrible and nauseous all day long. BTW: baby has been at the 50th percentile all pregnancy long, I didn’t have any changes in amniotic fluid or any other issues.