Agree with buffalo, could be a bad seal. Also agree if Revvy was feeling better he would give you an answer and advice better than all of us together. Checking gravity would take any guess work out, lazy way, look at it, has a krausen started to form (foam layer on top)? If so it's fermenting. Roughly what temp did you pitch at?
So the short basic version of a yeast starter. 18 to 24 hours before brew day make a 2000ml wort. Easy way is to mix 200 grams dry malt extract with 2000ml water ( 10 to 1 ratio ), boil 10 minutes then cool to pitching temp. I use an erlenmeyer flask so I can do it all in one container, in a pinch I've used a pot and once cooled poured it into a large mason jars ( only 1500ml). Add oxygen, put on a stir plate, swirl in the jar (every few hours after tge yeast is pitched too), something to help aerate the wort, add yeast, loosely cover with foil and but in a room temp dark place. You will see the ferment start. Next day make your beer then when you would add the yeast just dump in the starter. What this does is get the yeast awake, active, multiplying, healthy and ready to work. Now, this is just a quick simplified explanation of why, but enough of a how that if nothing else it will get you started with a " starter " and one step along in making great beer.