Advise needed please 😭

Le

So I did a internet cheapie on Friday and it was positive albeit faint it was line and it has colour, so now we’re on Tuesday and I done a Clearblue digital and it came back not pregnant. I am still 4 days away from AF so I know I’m not out but surely the Clearblue should’ve been positive as my hcg would’ve doubled by then? I refuse to buy anymore test as it’s depressing seeing not pregnant. I’m waiting for some more internet cheapies to turn up but I have a feeling it was a dud batch