My experience has been that a baby's sleep patterns can change for any number of reasons and for no apparent reason! If your husband has always snored, your baby is probably used to it, so I doubt that is waking him up. Motherhood is SO HARD, and I commend you for your choice to breastfeed and co-sleep. It sounds like the cold is just making him uncomfortable. Use a humidifier in your bedroom and try Little Noses drops and then suck the snot out of his nose. You might try keeping him next to you in your bed after he wakes up, as this may comfort him having you right next to him, and maybe he will sleep better. Read Nighttime Parenting and other books by William and Martha Sears. Starting right before 4 months my baby starting having sleep problems. Reflux medication to treat GERD helped, and I think she started teething then, because she got her first tooth at exactly 5 months. Between teething, reflux, and her high-need temperament (Dr. Sears decribes this in Attachment Parenting), I was horribly sleep deprived. It was a nightmare! Putting her in a crib only worked for a short time, and I found after trying every sleep trick in every book that the best I could do was continue to breastfeed and co-sleep in our bed and take naps whenever I could. Enlist your husband's help so you can catch up on some sleep. I can tell you, there will be light at the end of the tunnel, and hopefully this is just a temporary disturbance from his cold. Good luck!!