first time mom

i just missed my period and found out im pregnant via home pregnancy test but how soon should i see a doctor? should i just get a positive test from my doctor or an ultrasound? whats some really information i should know while trying to carry this baby thru the first trimester? (i recently had a miscarriage and i think it was bcus i didn’t know and was unaware of my diet?) im also not telling my family right away so i cant ask them anything.. ANY INFORMATION HELPS PLEAAAASSSEE