ETA: In response to the leaving her cry if you use my method she may wake crying but if you come right in and calm her, she won't be left to cry, and you may need to do checks in the middle of the night, until she realizes she is safe and you are there and she is okay without you. But in this method you do not have to let them cry. It does take a few sleepless nights on your part and commitment, but in about a week you will be grateful for a good nights sleep. Or you could also just leave her sleep on the couch until she is a bit older. Either way good luck!!!
Well the first thing you have to do is not let her fall asleep on the couch if you wnat to her be okay and understand where she is when she wakes. If she falls asleep on the couch she expects to be there when she wakes during the night and when she isn't it is upsetting and adding to the stress. So the first thing is that she needs to fall asleep wherever she will be all night. IF you don't mind her being on the couch all night, you can certainly let her sleep there, however i am one who believes in beds and sleeping in ones own bed. I co-slept with my daughter until she was 2 and a half, then with my son until he was about 3 or 4 months old. So I am not opposed to co-sleeping and think it is fine if you can do it, but I could no longer sleep with all the baby noises. I am a super light sleeper so that could be my problem. But there is no right or wrong way to sleep. So sleeping in her bed, your bed or on the couch are all fine. Now for me I would want her in her bed. So you need to start by having her fall asleep there. Melatonin can be a great sleep aid. So continue using it if it helps. But begin by putting her in her room at night, make it a nice peaceful bedtime routine, then sit with her, read her a story and then you can try various things depending on her tolerance. you can leave and let her fall asleep on her own if she can do that, it will be great, but most can't right away. so you will need to prep her for it. give her a hug and kiss and leave saying you will be back in to check on her and then leave, and then come back in in about a minute or so, to check on her, depending on her tolerance you can go shorter or longer. Extend the amount of time for the checks so she knows you may not come right in but eventually you will. At first you will need to return quicker til she gets it. If she cries or fusses you can go in but leave again saying you will be back in a few minutes to check on her. It will be a few nights of constantly running in, but after a few nights you can extend the time longer and longer, and usually within a week or so she will be falling asleep before your first check. The first few nights will be difficult tho. but if you stick with it, she will come to realize you are always around and checking in on her, and she will not feel left alone. I did this with both kids at various times. Just recently again with my son, but only took one night of doing now as he got it more quickly but have found I need to do it when there is major upset in their lives. Before that i had not done it since he was a toddler, and he is 5 now. So it worked well for us. There are other ways of doing a similar thing of teaching them to feel safe but stay in their beds, I know some have sat in the room, but it can take longer if you start with that, and slowly move the chair out but then you need to move onto the checks anyway. But whichever method you choose you need to be consistent and stick with it. If she wakes in the night, go in and say to her she is okay and you will be back to check on her in a bit. But don't stay until she falls asleep. Like I said the first few night will be difficult but it will get better quickly after that.