Sleeping habits

For a little over a week now I have been forced to let Samantha cry her self to sleep :(. At the beginning of last week, for two days in a row I would nurse her, she would fall asleep like always, but as soon as I put her in the crib she would wake up. I would then spend the next 1/2 hour rocking her till she fell back too sleep and I was able to lay her down, so by the end of it all I would spend a total of an hour putting Sammy to bed. By the third night I was kind of annoyed. That night she wouldn't even fall a sleep, after nursing on both sides. I could tell she was tired, but she just wouldn't go to sleep.
I guess it was time, if she wouldn't go to bed like she use to, by just nursing, I was going to have to let her cry. I felt so terrible when I left the room and heard her start to sob. I held off on doing it till now because from the very beginning she was alot better sleepier then Luke ever was and she is such a happy baby that I couldn't bare to have her cry.
At 9 months Luke was still waking up 4 times a night to eat. That was partly because he was so skinning that he didn't have the body fat to sustain him all through the night. We did eventually have him cry him self to sleep and the first night it took him 2 hours to finally go down, unlike Samantha.
I laid her down, told her I loved her and left. I was ready for a long night, but not even 2 min. after I had gone downstairs she had stopped crying. I couldn't believe it. When I went up to check not a peep was coming from her room. At first I was worried. In her fit did she stubble and bump her head, did she stop breathing. I told my self she was fine and waited a little longer before going in. She was fine, she had mushed her self all the way at the end of the crib closest to the door and had fallen a sleep.
This is how its been for a little over a week, but now she barely cries, its a big cry, but less then a min. and not only that, but she sleeps through the night now. She takes an afternoon nap and then goes to bed at 7:30 and sleeps to 7:30 the next morning. Some days I can even put her down for a nap while she is still a wake and she will go to bed after a minute of crying. We are thrilled to get more sleep and she is still my smileys all though the day even though I maker her cry at night.