Hi Sweety !
You did the right thing by not painting bare plaster - you'd still be painting now if you had done that - it sucks up paint like it has never had a drink !
Have you let the emulsion dry properly or only just finished the decorating ? If you've only just finished, then see what it looks like tomorrow. You might have to give the walls another coat - it depends on what colour was underneath. Nothing wrong with the focus brand by the way, I've got a 5L can of theirs from about 10 years ago and I still use to touch up my hallway now and then !
Can you take a piccie and post it on something like flickr or photobucket and then reply here with a link to that picture, so we can see just how good/bad your decorating skills are !