Really worried, please read!!

So 4 weeks ago I found out I was 4 weeks pregnant with my rainbow baby was over the moon cudnt be happier, iv been keep checking with pregnancy test to make sure the lines were getting darker and they did, but thismorning I took another test and the line was really faint me heart sunk , I have just done another and it again is really faint 😢what does this mean please someone tell me everything is going to be ok with my baby