Is it even possible to get a BFP at 8dpo?

Well... this is a bit of a shock. I'm now at 8dpo and have been charting my cycles with fertilityfriend, this morning I took a HPT just because I could, lol. I have actually been getting pregnancy symptoms, but I wasn't actually planning on testing for another week at least, but I had heaps of pregnancy tests and just felt like it. Well, I did the test and an extremely faint line (I mean REALLY faint) come up within the timeframe and it is a coloured line and is definitely not an evaporation line. I didn't even realise it was possible to get a BFP at 8dpo. I am a little scared because I suffered 2 miscarriages in a row within 3 months of one another last year, but thankfully found out what was causing them. Any answers would be great, am feeling quite shocked and a bit scared.