Sorry to hear that, man. That really sucks. Truth is, we all have a bad batch and/or brewday now and then. It's just part of the hobby ;)
It's hard to tell from your post what specifically went wrong but some things I always ask myself when things go badly are:
- was I in a rush?
- where did I cut corners and why?
- what parts were frustrating?
- did I guess or estimate things?
Once I find some things to think about there, I usually find what I can improve on. Whether it's giving myself an extra hour for "just in case" things, or maybe improving my gear somewhere along the way, or even asking about a way to do things.
For example, I used to use pH strips because I didn't want to spend $50 on a good meter. Eventually though, the strips became too frustrating and I purchased the meter. That part of the process is much quicker, easier and less frustrating now.
It's helpful to go back over any notes from the brewday too. I've gotten things mixed up on recipes before and only noticed it from my notes.
Hope you give it another go and better luck in the future!