Unfortunatel, they go through these stages. I NEVER let my son cry it out at night. you do what you think its best, but if 1.5 hours doesn't stop her crying, I think it is cruel to continue. She is 8 months old and you are the mom, you need to be there for her. You can never possibly know exactly what is wrong, but something is, so don't ignore her. My son is a great sleeper, but would go through these phases of about two weeks where he would stop sleeping and it would be hard to get him back. Then, he would go back to normal. I too did the rocking thing, but there were times where he would only sleep with me holding him. He is now two and I havent' seen him in the middle of the night since Christmas! I disagree with people who say you are going to spoil or get her in a negative routine by doing what she needs at the time, it didn't happen with us! Besides rocking, I do like the sound machine idea. White noise can really help, we used a cool mist humidifier at times. Also, is it dark in the room? My son has always slept in the pitch dark because I didn't want to use night lights. Starting at this age, every now and then, I have to turn some kind of light on and it calmed him right down. I put a night light in the bathroom next to his room. I open the bathroom door to give him some light and he will usually let me leave and fall back asleep on his own. Maybe she is just waking more often in the middle of the night and being able to see something will assure her. My son went through another bad stage at around 15 months old where he had to be on my chest to calm down. I would take him to the recliner and try to get some sleep myself. This lasted about two weeks and then stopped. Good luck, we all know how draining this is!