Hey guys, I need your help and advice please!!!

I'll give you a little back ground on my snake first.

I've had her since October 16th 2011. She was 3 months old then so now she's about 6 and some change. She's has a nice set up. Temps are right. (maybe a tad cooler on the cool side than it should be, but she's next to a window and it's winter...) She's only had one shed since she's been with me and it didn't come off all in one piece. I got it off later using the wet rag trick. (Works like a charm btw)

She's only missed two meals, one on the 30th of November, (she was going into shed) and one on the 21st of December, (I was out of town and got someone else to feed her. Maybe she didn't want it cause it wasn't me. IDK). I feed f/t btw. She was on live before but she changed over seamlessly.

Last Wednesday I fed her a 19g mouse. She weighed 212g when I weighted her last Wednesday. A little on the lighter side of a meal for her size. She is in blue (for a second time since I've had her) but I fed anyway.

After she eats, (Once every Wed) I leave her alone and don't bother her for a couple of days. Especially when she's in blue. I only opened her tank to mist the walls..

Today I noticed a smell in the room. After looking all over I noticed It was coming for her tank.....

I lifted the hide and saw a regurgitated mouse and a pile of poo. I cleaned it out right away. (She was in striking position the whole time not taking her eyes off of my movements.) She never has done that before.

I have some questions.

1.) Why did she puke up her food? (Stress from shedding)?
2.) That looks like a lot of poo. It that normal?
3.) Should I replace the substrate?
4.) Do I need to take her to the vet?
5.) Any general tip and advice PLEASE! I'm kinda freaked out on what to do.

I love her and just want the best for her. I feel like a bad parent.