Hi there My son is 10.5months old and I sadly ...

Hi there My son is 10.5months old and I sadly have to go back to work in a month. We have both enjoyed breastfeeding (something I don't want to stop but have no choice). He's on 3 breastfeeds a day + 3 solids a day and eats anything and everything. I have just started to wean him during the lunch time feed and he refuses the formula I give him in a beaker cup (which he has no issue drinking water out of). This has been going on for over a week now and as a result, his afternoon sleep is cut short because he wakes up hungry(even after a big solid feed). I'm worried that he is missing his milk and I'm reluctant to cut back any other breastfeeds until we've established a replacement....and I'm worried he wont be properly weaned by the time I go back to work. I was told to give him yoghurt or cheese but surely I can't do this after 3 solid feeds each day..wouldn't his milk be better? Hmmmm....am I worrying too much? Anyone have any advice on how best to wean? Any thoughts on going straight to cows milk given by the time I completely stop breastfeeding him, he'll be at least 11.5months? Any help would be appreciated.