Was it a bad start?
I get texts every day from someone I work with about how they threw that day. The skill level ranges from high school to big leaguers. The conversation typically goes "Threw well today, stuff was on, dominated", or "Didn't have it today, mound was terrible, just didn't feel right.", or "Pitched well for the first few innings and then I just sort of lost it." In these situations below we have a good start, that's it. There's an understanding of something not moving exactly as expected to get a desired result. And then there's a positive breakdown with a more elaborate self-evaluation of stuff and body. A common example that I'm leaving out is "Threw terrible, nothing felt right." This is an example of nothing went well, that's it.
In all of these situations there is something to learn from. Regardless of the outcome there should be something taken from the outing. I can't think of a scenario, even if it's the worst start of your career, that you can't learn something from to improve off of, but not if you don't write it down.
Maybe after you lost control in an inning there was something going on your body that was causing you to rush. Quite often when a pitcher starts to rush they're rotating too soon and their whole kinematic sequence unhinges. This is commonly due to losing the build-up of load into the back hip or the connectedness of the trunk and oblique slings.
Documenting in a personal notebook what happened and why you think it happened will help you get closer to being able to solve that problem sooner when it happens again or completely eliminate it from happening again depending on the issue. It's important to write down in a different section why YOU think whatever is happening is indeed happening
I recommend all pitchers, regardless of level, to keep a throwing log. It doesn't matter if it's just long toss or a midweek bullpen or an actual game. Keeping some record of how you throw will continue to improve your ability to identify and solve the problem. This process is even more important when something's not quite right in your mechanics and you're actively working to improve something. By going back to the notebook it allows you to incrementally improve every time.
They say history doesn't repeat itself, but it rhymes. Either way, get a throwing log.