What does this mean? I don't know!

chels • Mom of 2 👦 & 👼 baby

My son woke me up at 4:15 in the morning to come get in my bed. I fell back asleep until 5:50 ( which is usually when I take it) I noted it that I didn't sleep well. It dropped a lot. Is it just because I got up in the middle of the night or does it mean anything else?