Baby suddenly can't sleep alone?

While my daughter has not slept through the night since 3 months (usually wakes around 3 times a night) she's never had a problem sleeping by herself in the pack n play.

Now all of a sudden the last 3 nights she slept by herself for a few hours but then would just scream until I brought her in bed with my husband and I, and then she slept almost all night.

I just tried to set her down for bed and she was hysterical, I had to pick her back up. But it's only 6pm, I haven't even had dinner yet, she has to be alone for a few hours.

I feel bad letting her cry because I know she's been struggling hard to poop and she just cut a tooth, and had a fever last night so she's not feeling great so I keep picking her up 😭

Has anyone else delt with this?