My daughter fell off the bed last night

My precious girl who is 15 weeks today woke up for a feed at 2:30 am this morning so I put her in bed with me to feed. I was super tired because I only had 4.5 hours of sleep the night before so I fully intended to put her back in her co sleeper which is right next to my bed because I didn't want to take any chances (sometimes she does sleep with me, I'm in the middle between Dad and baby in a queen sz bed), but I fell asleep. I heard two little thuds in my sleep and my stomach dropped because I knew my dd had fallen. Omg it was the most terrible night of my life. She landed face down and her little cry killed me. Thankfully she doesn't seem like she was hurt at all. We called the nurse and the nurse just said to observe her for 72 hours since she didn't display any symptoms and was acting normal. I feel like the worst mother in the world and every time I look at her I feel fear and guilt. Oh man this sucks, but I'm so happy she seems fine so far.