3 Month Old: Eating & Diapers!

Lately, my 3mo old seems to be eating less & less. I try and keep him eating every 3hrs or so, but he hasn't been crying for food like he usually does. I'M the one watching the clock, then sitting him down to eat. I didn't think it was a huge deal, but I WAS starting to feel like my breastmilk supply was dwindling. NOW, he just woke up after being asleep for 10hrs an his diaper was barely wet! I feel like he has been having way less wet diapers for the last few days! Is my supply going away? Is he dehydrated? 10hrs seems like a VERY longtime with hardly any pee! Any suggestions?!  

Quoting LovelyLilMama:" Lately, my 3mo old seems to be eating less & less. I try and keep him eating every 3hrs or so, but he ... [snip!] ... few days! Is my supply going away? Is he dehydrated? 10hrs seems like a VERY longtime with hardly any pee! Any suggestions?!  "

10 hrs without pee does seem a long time but I'm no professional, our LO's are the same age and DS is sleeping a lot at the moment, they go through a growth spurt at 12ish weeks.
I would pump if you're worried. I BF and DS is having longer time in between feeds now though.
I would get some advice.

My three month old has also seemed like she is eating less and less, and I also feel like I am the one watching the clock. She doesn't pee much at night, either - I don't usually have to change her diaper at night, though after ten hours her diaper would definitely be soaked.
Are you feeding him at least 8 times a day?

If he is dehydrated his urine would be darker, his eyes would appear sunken, and if you pinched the skin on his forearm or the back of his hand it would stay "pinched" and not spring back immediately.

I think that they are just between growth spurts at this age, and at some point she is going to be starving and eating every two hours again and hollering until my milk supply rebuilds.

He JUST started sleeping through the night, and usually it would be soaked after 8hrs, let alone 10! This is the first time. When he wakes back up I will check his eyes and the "pinch". I'm hoping it's just a "down" period and it will pick back up. And yeah, I try and feed him every 3-4hrs which is usually 6-8 times a day.