After a year of trying I finally got pregnant but miscarried😢

It took me over a year to finally get pregnant and I miscarried this morning😢 I was 7weeks and 4days  . I went to the dr and everything seems to be ok medically speaking but I'm still in pain even though I'm resting and took some Tylenol. I have a backache and heavy cramping, when will it stop ? I'm just so crushed and idk what to tell my 3yr old who was so excited to be a big brother😭😭