Worried!!!

Natalie
Hi all!!
So I am
Panicking about whether I'm pregnant or if it's a chemical pregnancy etc...
I had a positive test on 28th Feb (non-digital) then another positive on 3rd March (digital).
I thought I could potentially be anything between 4 and 8 weeks as I thought I'd had an implantation bleed so I went for an early scan and she says she couldn't really see anything but poss very faint early pregnancy of about 2 weeks...that was on Monday (7th March) 
In a panic I took another non-digital test and it did come back with a very faint positive. This made me more panicked as I thought it must be bad if line fainter rather than darker??
So today I took a clear blue and that said I was about 1-2 weeks. Again I'm worried as I thought I'd be further along than that!!
Do you think it's a chemical pregnancy and my hcg levels falling???? 
I realise I probably sound ridiculous but I'm panicking!!!!
Thanks in advance xx