defu - don't panic about anything matey! You'll be dripping juice into the thing without thinking in a day or so! I use SR Boge carto's and I have (fortunately) found duds to be a rare thing. However, if I use high VG liquids, they tend to reduce in performance after a couple of days (I find anything 50% VG does this for me) and I vape moderately to heavily. When this happens, I chuck it and start a new one. On average, a carto lasts me three to four days max. The only tip I can give is to try a different carto and see if harmony is restored.
Cartos are the disposable bit of the vaping thing, unfortunately but they should last more than a day though - so you may have just got unlucky and got one which is prematurely tired! I spent ages when I first started vaping boiling them, vodka soaking them and even centrifuging them! They are disposable, and to be honest, if you try and revive them, it rarely works.
Maybe someone else can give you some different advice - hang on to the old one, just in case they do, and you can try whatever they suggest.