I feel like my 19m old is a glutton. Can eat a cup of rice with veggies for dinner and still latches on me for a good 3hrs nonstop before sleeping. My breasts are so sore. Is this just a stage or what?

19 months old is actually depending more on solids to make them full. So, I guess the 3 hours continuous latching is due to comfort latching. What you can do include: delay bedtime since he is not sleepy yet, distract him by bringing him to outdoor for a walk, offer additional snacks if he seems very hungry after dinner (finger foods, fruits, and etc.). If you feel your nipples are sore, try to apply some nipple cream to soothe the nipple.