Kathleen,
With proper care in making your bed safe for your infant to sleep and ensuring she does sleep on her back at this age, you have nothing to be apologetic about.
The reading I've done on this is that there is much more to SIDS than merely sleeping with your infant--in fact, there's much hysteria around it where there need not be. I'm certainly not a doctor or expert but I encourage you to read from those who are--those who are advocates of co-sleeping.
Books or readings I would suggest are anything on Attachment parenting by Dr. Sears. There is also a great co-sleeping nursing pillow called the Peaceful Pea nursing nest. You can read about it in a breastfeeding gear review I wrote for Divinecaroline.com at http://divinecaroline.com/article/22099/31698
I have co-slept with my son since he was 8 wks old. He just turned one year last Wednesday. After a year of co-sleeping I can tell you that my son is the most relaxed, happy, comforted baby knowing he has the security of his mommy by his side all night.
Also, when I was working and pumping at work alongside five other moms, those of us who co-slept were always MUCH more rested than the moms who had to get up, walk down the hall to thier sobbing baby to nurse and then get them back to sleep in their crib. Unless my son is teething, his night waking hardly disturbed my sleep (or his) and we both woke more rested.
Google Dr. Sear's website and look up the info on co-sleeping safety--talks about side rails or something where she won't topple off, ensuring she isn't close to a squishy pillow or comforter or wedged between two twin beds or something...and you aren't medicated or obese--it will give you peace of mind to know HOW to co-sleep safely.
I also spent a year in a mommy n' me breastfeeding support group and can testify, there's is clearly a link in milk supply and co-sleeping. My son has never had formula since he left the hospital (where I regret letting them give him any). I'm probably the oldest mom on here (I gave birth at 44) so it's a wonder my milk isn't dried up and sour! :-)
If you google kangarooing you'll also find some valuable information on the link between close mommy/baby contact and milk supply and the well being of your baby.
In most parts of the world infants co-sleep with their mothers.
I could never let my baby "cry it out" either. It goes against my mothering instincts. My son took many naps in his swing when he was small and eventually learned to nap in his crib or start out the night in his crib before coming to sleep with me.
I say, good for you and your baby! Le Leche league is a good source of local support and information as well. I know in pretty much every area there are weekly or at least monthly meetings.
L. & Ames (napping in mommy's bed right now with gaurdrails up)