BFP not getting darker 😥

Nicola • I`m a 32 year old teacher from the UK. Had my rainbow baby in September 2017 after miscarrying twice. Had a chemical pregnancy in January and now TTC #2
I had my BFP on Sunday and my test today was still pretty faint. It's a little darker but not much. I think I am around 14dpo and I don't feel any different apart from having sore boobs. I miscarried in March so I really hope it doesn't happen again this month. Should I be worried if my line is not getting darker?Â