Should I wake a sleeping baby?

Edit: TLDR: 5.5 month old who was on a good sleep schedule suddenly had a burst of energy. She went to sleep after 6am this morning finally. It's getting close to 12pm, should I wake her up or let her sleep?Hi all, I have a situation going on with my 5.5 month old baby. She's been sleeping through the night, for 10+ hours for a while now. This past week I've been able to get her to sleep by 8 or 9 and then she usually wakes up at 8 or 9, things were going great, we finally had a good routine going. Yesterday she had her usual naps, plenty of tummy time and even had some time outside playing. She ate good during the day as well. Nothing out of the ordinary.Then last night happened. I'm not sure why, but she just would not sleep last night. Come 7:30 we started the bedtime routine. Everything went the same as usual. I laid her in bed awake but drowsy, as I usually do, and left the room. Then she woke up and fussed. I let her for a few minutes because she will have some light fussing sometimes but then goes back to sleep after about 2 or 3 minutes. This time she did not, she escalated. I got her out, she was hungry. I fed her and she seemed drowsy so I laid her down again around 9. Then she was awake. This time she wanted to play, she was wired. We played some, she had a diaper change and I waited for her to show signs that she was tired or hungry. Nothing, just full of energy for 4 hours. By 1AM she seemed tired finally. So I went through her routine again and laid her down. And then she screamed, not just fussing, screaming! I got her oit because I sensed something was wrong, checked diaper, slightly damp changed it, tried to nurse her, she wasn't having it, fed her bottle she drank it dry and I fixed another. She fell asleep finally, I laid her down around 3am. I climbed in bed and passed out, about 10 minutes later she woke up again. Tonight was my night and husband said he would get up with toddler in the morning so I could sleep in, so I went to her again. Sang her songs while I walked around, rocked her and she fell asleep. I put her in bed and immediately she woke up, screaming again! She took another 2 ounces and a lot of cuddles. I thought maybe she was cold so I put her into a sleep sack. She finally went to sleep around 6:15AM. Then my toddler woke up (of course). I went to sleep and daddy had toddler duty for a while.It's now 11:40 and baby is still asleep. Of course, she hasn't been asleep for as long as she usually does. But I don't know what to do. I cannot have another night like that, husband goes back to work in the morning so I will have to be awake with toddler, no sleeping in if baby is awake all night. We can do shifts at night, but then we'll both just be tired.Should I wake her up now or let her sleep? If she sleeps longer is it going to affect her sleep tonight? Why did she stay up, why did she have so much energy suddenly? via /r/Parenting http://bit.ly/2HBgPgH