Anxiety effects bowels

I have been on anti anxiety medication for a long time now, i''m 26 and most days i''m ok however when I am nervous about something it immediately effects my bowels and causes me to have to rush to the toilet and generally have an upset stomach for days before the event i''m nervous about.

As its so rare I can usually put up with the extreme symptoms but now I have met a man I really like and get along with but just being around him or the thought of seeing him makes me nervous and means I am constantly rushing to the bathroom or thinking I will have to and I don''t know what to do, I feel that its going to ruin my life.

I am supposed to see him next week and already the thought of seeing him has caused me to have diarrhea and its making me think I should cancel seeing him. Help!!