Eating and a little bit of spit up

At Lucas' 2 week appointment his dr told us to only feed him 3 oz because 4 oz was too much for his little tummy.  I agreed and we followed the rules at home for about 3 weeks. We started to know he was getting fussy and we weren't sure why.  It didn't fit his personality so I decided to start feeding him 4 oz.  He took it like a champ.  He started eating 4 oz with no problem but then would eat every 4-5 hrs, sometimes even 6.  I didn't think anything of it.  I then started to notice that when he did finally eat he would scarf it down like he hadn't eaten in forever and afterwards he would spit up.  It's not "alot" but it does look like it.  It made me worry that we were over feeding him.  We started burping him about 3 times during each feeding but when we would pull the bottle away he would flip out.  His head would fly around, his little hands were flying and he would cry and grunt.  He didn't like it.  We tried to sit him up during the feeding but no matter what we did, he would still spit up. 

Today I decided to put him back down to 3 oz and try to feed him every 3 hours again.  We'll see how it goes.  He has been better about spitting up and he doesn't seem AS hungry when we finally gets a bottle.  I think we'll give him a 4 oz bottle before he sleeps tonight and see if it holds him over until E gets up for work in the morning.  I am going to see how this routine goes for us and if he's still spitting up at the end of the week I'm going to give his dr a call and see if we need to switch formula.  I want to do this before we buy anymore formula because its almost time for more and we have coupons that expire soon.  The spitting up doesn't seem to bother him but it bothers me like crazy.