5 weeks pregnant and petrified of miscarriage... HELP!?

i just my bfp on thursday... this is our seccond child and my husband and i are over the moon. but already i have been obsessing over worrying about a miscarriage... 4 of my friends have all had a miscarriage in the last 6 months and this baby is already so loved and so wanted i'm just so paranoid and i don't know how to stop myself. also im freaking out because my pos hpt was got lighter the next day when i used FMU do you think this can mean anything? bahh