Baby not eating

Syd • Sydnee I'm 25 • FTM • Prince Carter 💙👑 December 9th 2016•Excited • Blessed • and in love 👪
So I started back to work last wed and up until then my 3 month old son was ebf. He still gets breast milk when I'm away because I pump but he hates the bottle! We've tried 8 different brands so far and the only one he will sort of tolerate is the avent bottles. But when I'm away for 8hrs a day he only drink 3oz total that whole time! I've read that sometimes babies will do this eat just enough so they aren't starving and wait until mom gets back to nurse and make up for the little amount they ate. I'm just worried about him because some days he will just refuse to eat all together :( any other moms having issues with ebf babies taking the bottle? It sucks because I feel I'm ready to stop nursing but he totally is not.