I was healthy at the time I was going through college (despite moderate social anxiety which mostly just hurt my social scene, not academic performance).
My symptoms started in grad school, so I had to drop out of the PhD program and just get the Master's. I'm actually really impressed I was able to finish my thesis, as I was pretty depressed at the time. Real heavy feeling.
Personally, I DO think having a mental illness like SA in college can screw you over... but you have to keep trying and definitely definitely get the support you need, whether it be social or medical.