5 month old sleep struggle (please help)

[Littlebittasunshine]

So my 5 month old has been a bad sleeper from day 1. She wouldnt be swaddled wouldnt ever be put down would wake up every 2 minutes in her crib. I ended up sleeping with her on my chest for the first month until I had crippling back ache the midwife recommended I feed her to sleep, co sleep with her at my side on my breast. I stuck to that for three months more until the warm weather came and it's not safe for her in my bed now. It's too warm she gets hot and sweaty. I do have a good fan and windows open but it's still just too warm for her and I'm not comfortable with it. She has bad reflux and had awful colic for the first three months which didnt help matters. She'd cry for up to 6 hours every evening with tummy ache and being sick. We're passed this now but bad sleep habits have remained. The only way she'll nap in the day is being rocked to sleep in the buggy. At night I've tried to feed her and leave her in her bed with white noise or her mobile on but it doesnt work. Leaving her to cry isnt an option. She'll just cry herself into a frenzy then I'll have to try to calm her down for hours until shes calm enough to try settle again. I'll lay in her cot with her and try feed her to sleep but once she's asleep she'll want to use me as a human dummy (she wont take any dummies at all) and everytime I try sneak away she'll keep waking. It goes around in circles for hours until usually I give up and settle with her in my bed due to back pain and sore nipples. She'll still wake up several more times.
There must be an easier way right?!
My first slept through the night by 6 weeks so I know it can be done and I'm not doing something massively wrong. We have a solid day and night time routine. She is weaning a few weeks early due to her reflux. Shes a chunk and fed so much and was projectile vomiting all day long. The weaning has helped that.
Does anyone have any advice, any sleep training methods theyve tried?
I'm honestly so tired. I have no help and no advice with HV not working. Feel like I'm at my wits end. I need some rest but every night is a battle zone and I usually wake up more tired then when I went to sleep.
Advice appreciated.
Thanks

Could you create a sidecar cot?

This is a full sized, normal cot or cotbed and you remove one side. Then wedge it up to the side of your bed. It being bigger than a crib means that you can lie with your legs in your own bed, but with the top half of your body on the cot mattress and cuddling close to baby.

The idea is that once baby is asleep, you extract yourself back to your bed and you have not needed to move baby. It's really important baby goes to sleep where she stays asleep and is not put down while already asleep.

Baby then learns to go to sleep independently in the cot, but with your physical help.

On occasions of baby being very fussy, you can pull baby over to next to you in bed to settle, then instead of having to lift baby up to move back to the cot, you sort of "scoot" him across the mattresses. It's all bout teaching the baby to go to sleep in the cot and that's always going to be harder (and more distressing for a baby used to being cuddled to sleep) if the cot / crib is a separate entity.

I would go for a cosleeper cot too. My first slept through from 6 weeks old but my second didn’t sleep well until he was 3 years old, all babies are different so don’t compare.