first pregnancy help

my husband and I have been trying for a baby for just shy of one year now, I found out the day before my period that I am pregnant! sadly that's not the end. Our families both have miscarriage histories (his family not as much as mine, my grandmother had 4 miscarriages... one between each kid and my younger sister has had two... one of them being conjoined twins.) both our families also have twin history, (only this time his family has an insane twin count while my side has it a lot more sparingly) one of his relatives even have TWO sets of twins. I guess where I wanna get at is. . . 1- what can I do to ensure my child gets big and strong and beat the odds of my family's miscarriages? // 2 - my sister has a defect in her blood (rh negative will attack her fetuses in the womb of blood types dont match) the defect is extremely rare but it is passed from father to daughter so should I ask my doctor to check me for it as well? // 3 - my boyfriend doesnt want twins but I do should i tell him to suck it? ;) // WAIT AND 4 - if I begin spotting, at what point in the spotting should I worry about my child? /(spotting was pink, barely any and 4 hours later no sign of more but yknow...) I understand I might be over reacting, and that I could read this stuff online but sometimes information is just better from those who have gone through the whole shabang!! i spotted a tiny bit last night when my period was SUPPOSE to start. I have 3 positive tests tho so I know i am pregnant.