C25K: Week 5 Day 3

Yes, I'm well aware that I haven't been posting lately (even my Dad called me out on it this week -- thanks, Dad), but it's been a very stressful and emotional few weeks for me and this blog just wasn't that important.  But I have been running and keeping up with the Couch to 5K program.

Today was the dreaded Week 5 Day 3 -- the first "long" run:  20 minutes, no breaks.  Let's just say I was able to hit "Complete Workout" on the app, but it didn't feel like it.  Going into the run, I was certain I wasn't going to be able to complete it.  I mean, I had NEVER run anything close to 20 minutes in my entire life.  I felt pretty good starting out and even around minute 12 I was kinda impressed.  I thought maybe I could do it, until I started getting a super painful cramp near my diaphragm.  At minute 14, I had to stop.  It was just too painful.  I actually had to stop, double over for a few seconds and then had to walk.  I was not happy with myself.  At minute 17, I decided to run again, but had to stop at minute 19 -- with 1, 1 freaking minute to go.

So like I said, I can say that workout is over, but I'm pissed I couldn't run the whole thing.  How can I avoid these cramps?  Anyone have any advice?