My period is now going on 12 days late I took 2 tests about a week and a bit ago and they both came up negative just a few days ago I took another one and it showed a very thin faint positive line I thought it could have been an Evap line but the line was blue and didn't look like an Evap line I took another test this afternoon and it showed negative what does this all mean I'm so confused... Have only had a bit of nausea not much else... Please help!

I would either give it another week and try another test... or I would see the gp and ask about having a blood test done; stating that you had inconclusive results with the urine tests.

It may be a faulty test, while uncommon can occur; it may be an evaporation line, it may be you are pregnant and it is just early enough yet to not get a definite result on a urine test.