Who for how long did regression sleep last?

Who for how long did regression sleep last? How did you cope with it? What did you do? My little one has been without 3 days 5 months, but she's already been sleeping poorly at night for a month now, waking up consistently at midnight and then every 2-3 hours after that. It's hard to put her to sleep too. I don't try to feed her much at night so she doesn't get used to it and wake up every time, but without a breast she won't fall asleep. I forgot what sleep is like, when I last got some rest, even a little bit, I forgot I try to put her to sleep immediately when she wakes up at midnight