If it showed up on any test that your pregnant (even a very faint line is a yes!) You are! It is VERY rare to get a false positive and EXTREMELY common to get a false negative! A doctor's test is the best way to confirm, but if you had a positive on a test, then its right. It needs to detect the pregnancy hormone to even make the faintest line! Unless your taking medication that contains certain hormones, there is no way of having a false positive. On the box or leaflet that came with the test, it should say even if there is a faint line, its still a line!!
I think its safe to say congrats babe!
Some tests are more sensitive than others, like the clearblue may be 50 IU/L but the asda is 20 IU/L... that means the adsa one is more sensitive. (i dont know the exact ones on each-its an example)
And about the cheap lil stick ones-They WORK! It all depends on the sensitivity of the test. They all do the same job! Best place to buy is on ebay! Especially if your TTC!! I bought 100 tests for £18.99!!! And they came very quickly!! They even do the ACON Ultra Early tests which detect 10 IU/L!! (The lower the number the more sensitive!)
Anyway, all the best, let us know the results!!