My 6 month old has been waking up screaming and writhing anywhere from 1-3 times nightly for the past two weeks! She has very rarely slept all the way through on her own, but normally would go right back to sleep with a DF or NF upon waking without a problem.
Initially I thought the switch to a different brand of formula was to blame and she was waking from discomfort, but we've switched back to the original formula and she has no problems with any other feedings throughout the day. She is generally in hysterics when she wakes and has a very loud cry which wakes up the whole house. She is not comforted by a paci or rocking or shushing either

But...if we turn on the lights and let her "wake up" then she is as happy as can be! Not sure what to think about that as it sort of rules out any discomfort?
Here's the info
How old is your child?: 6.5 Months
What’s his/her daily routine? 4 hour EASY
Wake 6:30 | E 7:15 (6oz formula) | A | S 9:30-10:45
E: 11:15 (6 oz)| A | S: 1:00-3:30
E: 4:00 (6 oz)| A | E 5:30 solids | A | E 7:30 (6-8 oz)
S 8:00 PM | E around 2:30 am (6 oz)
What’s nap routine? 2 a day, sometimes a CN in the evening if daily naps were short
How long are naps? one short AM, one longer PM - she's never been a long napper though
What's bedtime routine? Time? solids for dinner, quiet play, bedtime bottle, asleep with no protest by 8
Do you bottle or breastfed?? originally EBF but now on formula and a few solids (sweet potatoes, pears, bananas, rice crackers)
How much? or how long? 6 oz
How many wakes per night? 1-2, they used to be very short and easy to resolve with paci or feeding
What’s your LO like when waking at night? How long is he/she up? Hysterical. Writhing and screaming even when held until we "wake" up and then she is smiley and giggling and ready to play with mom or dad!
When you go to him/her is she fussing or crying? Or is it a mantra cry? Screaming and panicked
What have you tried to settle?? Paci in crib, then holding to comfort, diaper changes, feedings, eventually she just wants us to be awake
What do you do for A time and how long is it? She has long A times by nature (a short napper) and goes to daycare so she is very stimulated throughout the day. Her routine is the same as it was before she started with these wakings
Are there developmental issues such as teething or milestones? A little more mobile and vocal, sitting on her own, no teeth yet
Do they have a prop? If so what is it? Paci she can put in herself
Do they have a lovie? No
Please help! I am thinking there is something I am missing here that is causing her to wake up so traumatically. I would really compare it to how older children can have nightmares/terrors...but she's still so young?