I used to smoke 5-6 cigarettes regularly for last 3 years. now i left it for last 80 days. should i need to worry about cancer or any health issues?

Worry is useless: I'm very glad you quit. You've increased your lung cancer risk slightly from baseline, but there's nothing you can do about it. The actual percentage risk over a never-smoker is hard to estimate & you'll be given different numbers, but it's low. Plan to live a normal life and enjoy being able to breath well, taste your food, and smell like an ashtray. Again, congratulation on quitting.