Vayne not healing on crits and no attack speed buff

at first it was all fine I was healing the first couple of days from my crit strikes then as soon as I try out a new build (stattik shiv, rapid fire cannon) I'm thinking I shouldn't have to go out of the way to spend gold on life steal items anymore then boom, buy the shiv crit and no heal or attack speed buff, I figure it might just be for that game but 3 days later I'm forced to buy bloodthirstwr as my third/fourth item as my masteries won't heal me. Find this very annoying due to the fact that I'm a vayne/adc main and would really like to try out some new full build paths without a life steal item taking up a slot