Baby won't drink from bottle but going back to work

Charlie

So my son will be almost 9 months when I have to go back to work for 2 days a week from next month (cue uncontrollable sobbing 😫), and he just will not drink out of any type of bottle. I have enough different bottles to start up a small shop, and have tried all different formula milks as well as expressed milk.

Due to circumstances he will have to sleep at my parents the night before and my mum will be looking after him whilst I'm at work but he won't be able to go for 24 hours at a time with no milk.

Has anyone else been in this situation and if so what on earth did you do as it's really stressing me out. My mum seems to think it will be ok to give him cow's milk as apparently I was exactly the same and she did that with me from 8 and a half months - but all of the weaning advice says different and if at all possible I would like to go with that.

Sorry for the long post but any help or personal experiences of this would be so great!