OP, I am so sorry for your losses. I agree with the PP that because your last beta was 4, this BFP is not from that pregnancy. I understand your fears and FX that you have great betas. If you have not already posted on PgAL, please do. They are wonderful and will understand your fears.
I cannot relate in this way. I am sorry for your loss. You might want to ask on the MC/ Pregnancy loss board, or the TTCAL board.
PgAL is the right board for you. If you go to TTCAL or the loss board it will be very painful for the majority of the women on those boards. TTCAL is not the place to post a BFP.