Spitting up and diarrhea

LO is 9 months, breastfed and eats solids twice a day.

Yesterday he didn’t seem to have much of an appetite but nursed nonstop. I ended up giving him a 2 oz bottle of pumped milk twice yesterday in place of his meals he didn’t eat.

Starting overnight, he had diarrhea several times and now is also spitting up after every feeding (hasn’t done that in ages). I tried some banana with him and he ate three tiny pieces before turning away.

How long do I watch this before I take him in? No fevers