Bid to the correct contract against a tough pair

I got the ♦ correct, pinning the Q♦ - I took the finesse, it holds and I then planned the next few tricks.  In my haste, I was then a trick ahead of myself and played the K♦ from Dummy instead of coming back to hand to make both ♦s - so cross with myself!!!  Make the plan and then carry it out in a calm manner.....