Hi!! I need some advice on my lo's sleep, I'm barely sleeping at night and I'm tired all day 
She's almost 6mo, she's had severe reflux all these months and is on omeprazole. She seems to be gaining weight better but her sleep has never been good. She's an angel baby and kind of able to fall asleep 'independently' but with her pacifier on. I put her in her sleeping sack, sing a song, put her paci in and put her in her crib and leave the room (with white noise). She usually complains and I have to come back a couple times to replug her paci and put her back on her side but I leave immediately and she eventually stops complaining. Very often she takes 30min naps, sometimes 45min, and usually one good nap (1h30-2h) in the afternoon. I usually put her down 1h30min after she wakes up from her previous nap, but I mostly follow her cues. She does not have a super fixed bedtime but at around 8pm, depending on when she woke up from her previous nap. One of my questions is if I should keep a consistent bedtime regardless of her awake time 
For bedtime we read a book, I change her diaper, put on her pijamas and sleeping sack and paci, I play a song and put her in the crib, and do the same as for naps. I leave the song playing for a while.
After that she usually wakes up after 45min as if from a nap (or 30min if she's overtired) and is quite awake, I nurse her to sleep and she usually wakes up every 1.5-2h all night, I try to stall nursing, sometimes it works for a little while sometimes it doesn't. She usually has a VERY awake period at night, about 2h or more (sometimes more than one period), I feed her and leave her in the crib but keeps making noises and moving around. In the end I usually have to resort to patting, but it doesn't make her sleep anytime sooner than she's ready to.
Please help :( Do you think it's a routine problem, schedule problem, self-soothing, all of the above?? I tried weaning the pacifier a month ago and gave up, and now I'm afraid she's too dependent on it and I don't know if it's helping her sleep or the opposite.
Any advice will be appreciated 