Am I a bad babysitter, or does this sound normal?

So, I'm new to babysitting. I have a lot of experience with kids through volunteer activities, but it's a bit different. I just got a job as an as-needed babysitter. I babysit two boys ages 4 and 5 (to make explanation easier: 4-Nick 5-Jeremy). I babysat for the first time 2 weeks ago, and it went pretty well, at bed time I had to bring out a bit of a strict voice because it was past their bedtime already, but other than that it was fine.

So here's the situation:

This time, the parents had friends come from another state and they brought a five year old boy (I'll call him Matt). The parents asked if I was okay to watch him as well and I said yes. Unfortunately, he didn't really get along too well with Nick and had different needs and bed time. The boys had missed their naps that day, so they were more cranky.

It was for three hours and we had a few problems. I took them outside, but it started to rain so I told them to go back inside. They ran upstairs and went into a room and locked the door. I told them to open the door several times and no one came. I called the mom and she told me where the key was, but they then opened the door. I gave them a stern talking to and took them downstairs.

Later, Nick pooped himself and took him to the bathroom to clean him up. But while I was doing that, Matt and Jeremy started fighting. I gave them both time outs, and they were fine after that. They wanted popcorn, but I said that they had to be very good for 20 minutes first. I made them popcorn then, and got them ready for bed.

All went well, it was a little crazy, but I finally did it. I thought they were asleep, so I went downstairs to start cleaning up. But Jeremy and Nick started fighting over stuffed animals. I went up and down the stairs several times trying to find the requested stuffed animal, but couldn't find it. I told him that I brought up a bunch of stuffed animals to share, but Nick kept fighting. They were being very loud, and were keeping up Matt, and they kept it up for at least 10 minutes, too.

Finally, I had to bring out my strict (and I guess kinda mean, too) voice and they finally stopped. Not too soon after, the parents came home and all of the kids were calling for mommy. Nick was really happy when I was alone with him reading stories and playing before bed (probably because he was used to having all of the attention on him, and didn't like to share it), but was upset that he'd been kept up. I don't know what I could have done about Nick, I guess he was just extra cranky because of having company over, but I feel like should have done more.

What should have I done, and would you consider me a bad babysitter?