The advice you are receiving is a bit one sided and it sounds like you are not totally comfortable letting your child cry. There is much research that infants are not ready to self sooth and your baby is needing you for many reasons during the night.
At six months there is typically a greater need for mom because of so many growing things happening. Especially teeth and they are painful coming in. (I recommend "Childrens" teething drops. My 9 year old daughter says it tastes okay and works fast. She was working on her second set of teeth while her brother cut his first.)
I am a nursing mom and have many nursing mom friends. Typically, we keep our children close in the bed and nurse on demand and find that it is fairly easy to sleep while nursing. Sleep is fragmented but less stressful to fall back to sleep.
One way to look at it is that parenting is a 24/7 job and when children are very small they need you more. Believe me, as a parent of a 9 year old I wonder where the time went. Now she is sleeping over at a friends home almost every other weekend. I'm just saying that things will change so hang in there and find times to nap to catch up on sleep.
Here is a link that explains night time parenting http://www.attachmentparenting.org/principles/night.php
A good book to read is
'Good Nights: The Happy Parents' Guide to the Family Bed (and a Peaceful Night's Sleep!) (Paperback)
by Maria Goodavage (Author), Jay Gordon (Author)
This book will not show you how to MAKE your child sleep but will help you to understand sleep and what infants needs are.
Following is a quote for you. I am sorry that I don't have the reference for you. Also are some links to articles that can help you to understand some development issues and scientific findings and research.
"New research suggests that these techniques can have detrimental physiological effects on the baby by increasing the stress hormone cortisol in the brain, with potential long term effects to emotional regulation, sleep patterns and behavior. An infant is not neurologically or developmentally capable of calming or soothing himself to sleep in a way that is healthy. The part of the brain that helps with self-soothing isn't well developed until the child is two and a half to three years of age. Until that time, a child depends on his parents to help him calm down and learn to regulate his intense feelings."
http://observer.guardian.co.uk/uk_ne...345420,00.html
http://www.nd.edu/%7Ejmckenn1/lab/culturalarticle.html
http://www.kellymom.com/parenting/sleep/sleep.html
http://www.nd.edu/~jmckenn1/lab/longterm.html
http://www.nd.edu/~jmckenn1/lab/babysleep.html
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I hope you find these resources helpful in finding creative ways to find solutions that work best for you and your family.
L. :)