Potty Training! (and sick?)

So, we knew Jack was getting close to being ready to potty train... I would have loved to have him potty trained a long time ago, but he just wasn't ready... But lately he's been showing more interest in it, so we thought he was finally ready.
We wanted to do it over a weekend when we could stay home and not go anywhere, and this was the first weekend we had, so we decided to go for it!
Jack and I went friday night to pick out some big boy underwear and a toy that he gets when he can go without accidents. He was so excited!
Saturday morning started with 2 accidents right off the bat. I was setting my alarm for every 15 minutes, but the first time he peed, and then the second time he peed and poo'd... needless to say I was beginning to question his readiness (mostly because I had just taken him to the potty!)
But, after that he went down for a nap in a pullup (which was just barely wet when he woke up) and when he woke up, I took him to the bathroom, put him in his trainers, and it's like it just clicked for him. We went the rest of the day without any accidents! (Except one, but he was in the doorway to the bathroom taking his pants off and just didn't make it to the toilet, so at least he was trying!)
So, we ended the day on a high note, and I am excited that he really is ready, and he is getting it!
He loves putting pennies in his piggy bank, so whenever he goes on the potty he gets a penny for his piggy bank, and if he wants a sticker or a piece of candy he can have that too. (Though he forgot about those ones most of the time, he was more excited about the pennies!)

So, 1am rolls around and he wakes up, so I go in there and he has thrown up all over his bed and himself, and had a 100.6 fever. Not sure if it's a stomach thing or if he was coughing and threw up. I've heard him coughing a couple times, and it sounds like maybe it could be croup... I've never been around it, but I hope it's not! He isn't coughing a lot, but when he does, it sounds harsh, and almost like a seal (which is what made me think croup...)
But, it is 9am, and he is still asleep, which is very rare, so we will see how he's feeling when he wakes up! Hopefully it is just a regular cough/cold, and not croup!