My 2.5 weeks old newborn is waking up every 1.5 to 2 hours after latching for 30 to 45 minutes (alternating breasts when he unlatch himself). However, when He's given medela calma bottle (80 ml), he's able to last 3 to 4 hours. His diapers output are ok. When I pump out At his feeding time (when replace with bottle), I get -about 100ml each side. Wondering is it sign that he's not getting enough from latching and I should change to bottle?

Just to add on, here is an article which listed some signs that baby may not be drinking enough: http://www.babycenter.com/0_how-to-tell-whether-your-babys-getting-enough-breast-milk_617.bc?page=2 If your baby is gaining weight, and diaper output is alright, there should be no need to worry about the latching and the amount he is drinking. Like what Vanessa mentioned, it is very likely that your baby is nursing for comfort.

Sometimes baby want to have comfort latch which happens to my baby too. If you notice, they don't suckle throughout the 30-45mins which means they aren't drinking for so long. Majority of the time is dat they are sleeping dat is why we have to disturb them when they drink to ensure they r drinking enough.