Could i be pregnant???

I took three pregnancy tests and one of them had two lines but one was visible and barely had color I took the new clearblue digital test yesterday and it said not pregnant I took another clearblue digital test this morning and it said the same thing I have irregular periods but this app soon my period is due March 24th..and other app I have got the 28th but I had sex on my fertile days and when I was ovulating but I had positive ovulation tests for a whole week and some days doe could I be pregnant??