Yup, been there, done that. Haven't we all? LOL but not fun at the time.
What I do now is set price alerts above where I have my mental stop, and when my computer starts dinging me, if the stock is dropping like a stone, I just send a sell-at-market order; if it's simply a trade going in the wrong direction, I do a sell order 10-25 cents lower (where my hard stop would originally have been) but don't send it until the very last moment. Maybe not the best method, but it works for me (except when I ignore the dinging because I'm deeply enmeshed in another trade at the moment).
N2B