Pregnant again after 2 miscarriages?

hi, i had my wonderful son in sep 06. in june 08 i had a silent miscarriage at 7 weeks but found out at my 12 week scan. i was devistated. in nov 08 after separating from my husband i found out i was expecting twins but i lost that pregnancy as well at 9 weeks. i am now pregnant again with a new partner and am about 6 weeks gone. not only am i petrified of it happening again but i think it might be twins again. not only have i lost twin but he has in the past as well and not only that but he was one of a twin that died at birth. is there anyone that can advise me or been in a similar situation????