Threatened miscarriage again

Aislin
Had a miscarriage in May at 6+1.
I got a BFP last week at 10dpo. 
Since then I've some intense cramping and spotting, which have now stopped and during that time my tests got light and I was certain I'd lost it but the tests are now getting darker again - although the clear blue digital still has me a week behind where I could possibly be (I could be further but I couldn't be less) They're sending me for a scan on the 23rd of December when I'll be 6 weeks exactly.
I know cramping and spotting are normal during early pregnancy but the test dipping? I took 3 and they were all really light (two with FMU one with a hold) but today's is quite dark (pictured). 
Has anybody else had a dip in the hormones and then gone on to be fine? I've seen quite a few complaints about the clear blue having the dates wrong so that on it's own wouldn't concern me too much.