7 months old and still walking up all through the night?

i've always argued that i will never let my baby cry because i want her to develop a sense of trust in me and i've read that when u respond to ur baby's needs promptly and with care early on, they grow into more independent and calm babies and toddlers. the theory is yet to be proven in my baby's case, who was incredibly fussy and difficult since birth. everyone including my own mom told me to just let her cry,but i never did. it has gotten much better since birth but in the sleep department, it only got better for about a month when she was 5 months old (she would give me about 5 hour strech of sleep) then we're back to waking up every hour or two. she needs to be nursed to sleep which i tried to stop several times but its just really really difficult, i've tried for about a week to just pat her and calm her but it goes on all night and by the end of the week i was a wreck. right now i finally got her to accept a pacifier thinking she might suck on that all night and sleep but ofcourse the pacifier falls and she wakes up and she would refuse the pacifier and just want to be nursed to sleep. it gets to the point when she grabs my or keeps banging her head on them till i give in. i have to nurse her and or hold her with a pacifier to sleep for naps and for bedtime and all throught he night when she wakes up which means basically i do that for like 10 times a day. its exhausting really. and its not just that i'm tired i'm a bit disappointed, i feel like i failed to be a good mom and teach my baby how to fall asleep and stay asleep. once i was sick and had to go to the hospital and stayed for the night and my mom stayed with her, she wouldnt sleep till 3 am all the time screaming and then she slept for an hour only and woke up hysterical and my mom had to bring her to the hospital. what am i doing wrong? i read all the books and i try everything in my power. i only tried to let her cio as i periodically check on her once, and she cried for an hour and didnt fall asleep. what should i do?