First time pregnancy, HELP!!

So I went to the ER a couple days ago for a migraine that lasted over a week and an extreme pulsating tinnitus in my ear. Well I'm about to get a lumbar puncture done to test the pressure in my brain, when the doctor drops a bomb. My blood hcg test came back positive, very faint, but positive. She explained that I could be a week or two pregnant, and that I need to do a urine test at home in about a week.

She also said that it's possible that I could just miscarry with my next period that's due in a few days. I dont know what to do. My fiance and I are well off but I'm still very young(20), and hes 25 so he's more than ready for kids. I just dont know where to begin looking for information or what to expect. I dont want to get lost in google, and start believing crazy stuff like my baby could grow an extra limb if I use scented deodorant ya know? Haha

Any advice for someone whose pregnant for the first time? I obviously cant tell my family because it's so early, but I need to know where to start.