Your post really hit home in some aspects. I developed IBS while in university and can still remember the day it happened.
I know what you mean about the panic attacks. I used to get that feeling of dread that you described and felt uncomfortable discussing it with anybody. As a result, I withdrew from my neighbors in the dorm. Any emotional connections that I had previously were severed. I thought that every sleep would be my last.
I endured this for over a year. At first it consumed 95% of my idle thoughts. Then 90. Then 85. Etcetera. Then 10. Then 5%. And finally I was able to suppress it.
So I am pulling for you. Do something to get your mind off it! Stick with it and you will get through it.
Keep trying to get your stomach under control. Believe it will happen. My stomach still gets the best of me at times, but it is 10x better than it was a year ago.
Last, DON'T SABOTAGE YOURSELF!!! I'm gonna say it again -- don't sabotage yourself! If you keep giving your G/F the impression that you aren't good enough for her then you will lose her. Do not use IBS as an excuse for not trying new things.
Keep at it. I'm pretty sure that many of us here have felt defeated by this debilitating condition, but found the courage to deal with it and eventually rise above it.