Hello and congratulations!:)
So you must be 4 weeks. Firstly, it's up to you to tell who you like when you like. Some people are superstitious, some not. I was until I had a miscarriage at 11 weeks earlier this year. Hadn't told anyone except my parents and then ended up having to tell everyone because of needing time off work etc. Now I'm pregnant again I didn't care who knew!
Give the GP a call tomorrow. They'll probably want to see you to refer you to the midwives although in some places you contact the midwives directly. If you do see the GP, don't be disappointed with your visit. They don't test anymore as home pregnancy tests are as good as anything they can do. They might make a fuss of calculating the due date. They love doing that so let them even though you've probably looked at 18 different online calculators!
They might ask if you're happy with the pregnancy in case they need to refer you for other options. This is a standard question.
You'll get an appointment with the midwife for anywhere between 8-12 weeks for your booking in. A long long appt where they go through the family history of you and the dog blah blah.
Then you'll get an appt for 12 weeks for your dating scan and, in a lot of areas, nuchal fold scan. This is where they calculate a risk for Downs Syndrome.
So, it will feel like a long time before anything happens but you'll have lots of tiredness and hormones to keep you busy! And there we have, the beginner's guide to early pregnancy!
Good luck :)