A bad combination = panic attack

So here's a little background..... I'm a pharmacy student under a lot of pressure right now. My schooling literally doesn't allow for me to sleep. It is also 2 days before my period. Emotions = very unstable. Well today at work I had a patient harass me for 20 minutes and then finally my body went into panic mode. I had the worst panic attack of my life and I ran out of the pharmacy crying my eyes out and then my manager had to send me home because I couldn't calm down. It's been on hour since the event and my heart is still racing. Needless to say I'm super nervous to go to work tomorrow because I'm so embarrassed. Has anybody been through a similar situation? How did you deal with it?