Sleep issues!

My Baby Kambria has some major sleep issues, she sleeps way under the amount she should. She cries and so mommy is a sucker and goes and picks her up and talks to her and she has caught on apparently, and doesn't sleep, just cries. At her 6 month check up I was telling the Dr. what a horrible sleeper she is, he stated that I needed to put in ear plugs and just let her cry :0( Yeah not going to happen I thought to myself as I said okay to the Dr. Well it just keeps getting worse and worse .... in return, mom gets no sleep so she is tired, ornery, and useless.
I was talking to my sister and telling her how hard it is, she suggested the following method.
Put Kambria to sleep, allow her to cry for 5 mins, go into her room and comfort her .... however DO NOT pick her up. Leave the room once she is calm and allow her to cry 1o mins this time unless she goes to sleep, if still crying after 10 mins go in and comfort her again, leave and let cry for 15 mins, you then repeat the 15 mins until she goes to sleep.
This sounded way too hard for me, I really feel like a jerk to let my little baby girl cry ..... BUT I need my sleep. So today when she would not take a nap, and I was getting frustrated, after getting only 4 hours of sleep last night (Marshall was up with high fever all night), I decided it was time.
I put Kam in her crib, she gave me the sad eyes and I walked out, she began to cry, so loud, so hard, so sad ..... I sat in the kitchen listening to her cry .... counting down the 5 mins feeling like the worst mom in the world. After 5 mins I ran in her room, put her Binky in her mouth rubbed her tummy, said I was so sorry, talked to her and almost cried. She calmed down and I walked out ..... so wanted to pick up my little girl. Went back in the kitchen, Kam starts crying then stops after about 2 mins, go peek in and she is sound asleep. YEAH :0), she is asleep faster then it would normally take, and she didn't have to be held or fed to go to sleep.
I here you have to do this about 2 or 3 times before they understand and it works.
I will continue this for I know it is best for us all. Lets all hope it works like a charm tonight!!!!