I’m afraid I can’t carry out my pregnancy, what should I do?

Hi i am a mother of two both preterm deliveries..my son was 8 months born viginal delivery…my son is 18 months old…i got pregnant with twin girls they both were born via emergency c section after my water broke…my one daughter died other was in hospital for 3 months she got released on nov 2016…from release date she is now 3 months old..and im pregnant again 3 to 4 weeks max im weak o cant carry this pregnancy what should i do…