Contraceptive pill query?

I am trying a new pill with lower hormones and 18 days into my first packet I started bleeding. I carried on bleeding until part way through my pill free week and then stopped earlier than what I would of done normally. I'm now on my second packet but I'm worried if the bleeding would of made my pill less effective. As a result at the moment I'm using extra contraceptives as I'm terribly paranoid that the pill won't be covering me properly, even though I have taken all my pills as I should. I know its not unusual for irregular bleeding when you start a new type of pill as it states it with the leaflet that came with the tablets. Should I be protected enough on my pill against pregnancy or not? Any advice would be appreciated.