help! my lo's up a million times a night

For bf mamas who used to nurse your baby to sleep, how did you get them to sleep without the boob? My LO won't sleep without it and I'm beyond exhausted. She used to sleep a solid 5-7 hours without waking, but now she's up from 4-7 times a night. I tried a mild version of cry it out but I caved after her 2nd 45 minute bout of crying. She's teething too. Any tips or tricks to help us get some sleep?