Bottle Probs

Eric is 7 weeks old and has taken a bottle here and there (about every other day) since the hospital (my milk was delayed coming in so we had to supplement with formula at first). Now it seems like he HATES taking a bottle and has difficult latching to it. I haven’t even been able to give him one myself. I go back to work in a few weeks so I really need him to start taking it. Plus I don’t always want to have to BF when we’re out. Any advice or similar experiences?