Late AF

So AF was due on Wednesday this week, I'm usually like clock work and never ever late it's now Friday and still nothing. Did Clear blue digital plus last night and it said negative. Trying not to get my hopes up but as we've been trying for over a year it's difficult not to. Has anyone experienced negative in early pregnancy and then got a positive result? Have read lots about clear blue not being great with early pregnancy etc..

Went to Dr's (not my usual GP) & he said I could come on in a week and could just be delayed, don't think he was experienced enough in the subject and didn't even suggest in doing a test there where they have in the past... so confused atm, going to wait until tomorrow am to do FRE and hope it's BFP!!!