8 weeks late

I'm 8 weeks late, normally as regular as clockwork because I'm on microgynon. Had home pregnancy tests and 1 at the doctors. All negative so the doctor told me to keep taking my pill as usual and hope I drop back in to sync. I haven't and due to start my next pack soon. I fell pregnant with my first child while taking the pill and I'm convinced (secretly hoping) I'm pregnant again.
Any suggestions on what to do?