Going back to work

So my lo is 9 weeks now and I’m going back to work at 12 weeks. I have a few bags of milk in the freezer but mostly I’ve just been feeding him directly. The few times in the last couple weeks I left him he had roughly 4 oz each time. However when I pump I don’t get that much and I’m really worried about going back to work. I work a job that is hourly and I’m worried I won’t have time to pump everyday and on schedule.

Also we don’t have very many bottles, been using either the minbie or the dr brown bottle but we need a lot more for day care. I can’t decide what kind to get. Suggestions? Advice? I’m freaking out.