I hope that I can be of some help. I'd first make sure to rule out anything medical. Keep a close eye on on what she does and when she does it, her reactions to your actions, and then let your pediatrician know what's happening so that anything medical can be ruled out.
When my son was an infant, I was fortunate enough to read an article that helped me find a happy medium between leaving my baby to cry himself to sleep and picking him up each time he cried.
For the first week, I'd rock my son to sleep and then place him on his back in his crib. (I do not think you need to miss out on rocking her to sleep and it doesn't hurt the baby.) If he woke to cry, I was there immediately, did not pick him up, made sure he was safe and didn't need a diaper change, and would quietly tell him I loved him, he was safe, and it was time to sleep. I would softly touch him, maybe rub his tummy a little, and then step back. I would assure him with my soft words that he was loved, safe, and it was time to sleep. Slowly, I'd make my way out of the room.
The next week, I added five minutes before responding. I'd repeat the process. If he wasn't asleep by the time I left the room, I waited five minutes before starting over. However, I didn't pick him up unless he needed physical attention such as a diaper change. I would gently touch him and talk to him and slowly make my way out of the room.
The next week, I'd add another five minutes before responding. I'd repeat the process and add minutes when needed; however, I think I rarely had to let my son cry for ten minutes because this process worked so well for us.
Note, that if your baby becomes sick or some event changes the schedule, you'll need to start this process over again. And, I have to encourage a scheduled bed time and a familiar routine before bed. The routine helps the baby feel more comfortable. Babies need a lot of sleep and they like schedules. Mommies and daddies need sleep as well and some grown up time.
Also, young babies like to feel safe. If you're not still wrapping her snuggly in her blanket, you might try it. Also, there are those baby chucks you can place on either side of her to let her feel safe and snug in her crib. I used them with my son.
I do agree with making sure the house has it's normal sounds at sleep time for the baby. You don't want to always tip-toe around the house.
I hope that this works for you. It sure worked great for my son and me. I was 30 when my son was born and I've always been a single mother.