Rule of thumb: Make a habit of not adding cream to any sauce or gravy when it's cooking, that's one of the main reasons the cream splits and gravy or cream doesn't give the desired results.
If you don't have chicken powder, add one chicken cube (stock or knorr, there are two cubes in one small box) instead. If you're adding chicken cube, remember to omit salt, otherwise it'll get too salty.
Cling wrapped, it stayed fresh in the fridge for 6 days.
Sauce maybe runny in beginning, but it'll get thicker once it reaches room temperature so don't thicken it way too much while cooking.