Several of my family members have cancer of colon, prostate, also lung. I was diagnosed withfibrocystic breast disease. Would I be a high risk?

No. Often there are families that have a number of cancer and their is no obvious correlation. Fibrocyctic disease makes it harder to examine as the breast seems to be lumpy but does not put you at more risk. If there were first degree (mom or sister) or several second degree relatives with breast cancer you would be higher for breast cancer risk. In that case brac genes can be tested.
Screen. We live life one day at a time. Practice healthy life style, be optimistic. There is nothing more powerful than the mind, even in adverse situations. You need proper cancer screen and your doctor will help you with that.
No. Somewhere between 99% and 101% of women get "fibrocystic change" sometime during their reproductive lives. It's ordinary, common forms are a non-problem. Keep up surveillance against cancer and you'll be doing yourself a huge favor. Best wishes.