So let me get this straight:
Got a Dividend Check
Went to sell stock, see it's a large amount.
Got scared and want advice.
Here is my advice. Stick to your plan. Only delay if you would have to pay a significant amount of taxes for the sale. (ie spread out your tax bill over years if you must.) If the stock in question no longer fits your Investment Policy Statement (IPS), get rid of it and put your money where you stated your going to.
Now if you have a reason, like say you feel this company is awesome and could go up more. Fine, call it play money and keep it as is. But I don't recommend doing this to most of your holding that do not fit you IPS.