G.K.
Welcome to the normal middle of the spectrum! I say that without sarcasm.... Did you know that 52% of 2 year-olds do not sleep through the night? Did you know that breastfeeding toddlers are nursed to sleep an average of 5 nights per week? These were interesting facts that helped me understand a little better why my 2yo STILL doesn't sleep through the night consistently. I've always had sleep issues with him, so I'm jealous of any Mom who is blessed to have a good sleeper, but honestly, the sleep patterns of your 8mo sound completely normal, even if that's not what you're "used to."
Studies also show that what babies, infants, toddlers, etc eat during the day have no bearing on their sleep habits and patterns. At 8mo, he may be teeting, he could be going through a growth spurt, learning a new skill, etc etc. Or it could be that 16 days of nursing back to sleep and sleeping with you showed him the "good side" of life. My son loves to sleep in Mommy's bed, but I'm too light a sleeper to enjoy bed sharing. There could be many reasons why your son is experiencing these changes in sleep.
If it helps, I make sure there's a bottle of water in my son's crib (since he was about 9mo), so that he has something to drink if he wakes in the middle of the night. Try that for a few nights (or as long as you want because it's water). Try to take this change in stride and know that his current sleep habits are normal and will change many times in the coming years!