Please tell me my baby isn’t upset with me

So we recently used the Ferber method on our 5 month old when she hit her sleep regression (hard!) and it worked remarkably well. Since day 4-5 she’s been sleeping through the night and putting herself to sleep with like <2 minutes of crying. She normally sleeps from 8pm to 6-7 am. Last night, I put her to bed at 8. She woke up crying at 3:30am and I discovered she had a poppy diaper. I changed her and nursed her a little bit and put her down and she put herself to sleep relatively quickly. She then woke up at 6am. I heard her on the baby monitor. She was laying there talking to herself. I decided to give her a minute because she looked sleepy. Unfortunately, I fell back asleep and at some point the baby monitor died. I woke up again at 8:30 and when I went in she was still laying there talking to herself. So now I’m worried she was laying in her crib awake for 2.5 hours waiting for me. But maybe she fell back asleep in that time? Even with sleep training, she would’ve cried if she needed something, right? I’m so worried she felt alone in her room that whole time wondering why I wasn’t coming to get her. I’m so hoping she fell asleep, and maybe just slept later because she got topped off with milk in the middle of the night.Maybe I’m overthinking this via /r/NewParents https://www.reddit.com/r/NewParents/comments/178fdnk/please_tell_me_my_baby_isnt_upset_with_me/?utm_source=ifttt