Hi, I am on the pill and I am on my 7 days break. I had unproteceded sex last Friday and also on the weekend. My period is due this week. I am due to start taking my pill on Friday but if I don't have a period should I just take the pill or do a pregnancy test.

Take a test first. Very important to. In case you did become pregnant you don't want to harm the baby nor yourself. But a lot of times when taking birth control it can throw off your cycle. But be on the safe side. Say you became pregnant and you continued birthcontrol during your early pregnancy, a painful miscarrage will happen.

If you have been taking the pill correctly during the 21 days, you are protected during the 7 day break.

I have taken the pill for the 21 days and also taken it about the same time every day

Part of the deal with the pill is that you can take it and not have to worry about using any other form of birth control. You are protected during the 7 days off if you are using the 21 day count... and obviously still protected with the 28 day count since the pills that are taken those 7 days are not actual birth control pills but simply a way for women to stay in the habit of taking them on a regular basis.
When taken correctly, the pill has a high success rate of preventing pregnancy... not STDs of course, so that is another consideration that some people contend with.