Going through similar here and 4 month vaccines plus teething are making things extra.... challenging.
My DD was also going for a good 6-7 hrs with maybe 2 wakes a night but since 14/15 weeks began waking 2 hourly and being v difficult to settle (wouldn't feed to sleep).
I took FATE's advice and took the side off DD's cot and pushed it against our bed. I'm also using a blankie to cuddle into her during bedtime routine and night wakes though I know it'll take her a while to latch onto that for comfort.
When she wakes now I cuddle up beside her and hold her hand and put another hand on her tummy and sometimes it gets her back to sleep without her needing to feed to sleep. If she wakes again within 30 mins I automatically feed her but again, like your LO, she still requires "settling" to go back into cot so I do the hand holding routine if needed.
Last night she took aaaages to get to sleep but slept 10pm till 3ish and then when she woke again at 5am a hand hold got her back to sleep again with fairly minimal fuss, so I know she'll get there eventually!
I also agree with napping and feeding the bejesus out of them during the day. DD definitely has better nights of she's had days of good solid naps and full feeds.
It WILL get better but you probably do need to adjust your expectations a bit. My DD1 took about 2 months to self-settle again at this age, and nose-dived again around 8 months with separation anxiety. First full night was at 10 months and consistently sleeping through around 12/13 months.
Could be shorter or longer to that blissful milestone for you but remember it will happen!
Sympathy and fist-bumps from the Sleepless Sisterhood to you