You don’t to tell your doctor tomorrow unless they are likely to give you medication that isn’t safe in pregnancy. You don’t need a doctors appointment when you get pregnant, you just need a midwife one around 8 weeks.
This isn't true everywhere - I've just found out I'm pregnant and have a GP appointment tomorrow to get referred to maternity services. I would've quite happily self referred to the midwife, but it's not an option in my area/surgery (not sure which).
OP, first of all, congratulations. 
Agree with what others have said, there is very little intervention in a healthy pregnancy. I had NHS care and did NHS hypnobirthing classes, my hospital had a MLU which has a fantastic reputation locally, I could've had an NHS home birth.
The scans, urine tests etc can flag up problems early, which means they can be fixed before they become serious. For example, if you have gestational diabetes, best to know, watch your diet and stay healthy rather than continue unaware.
I was surprised at the extent to which my opinion was considered within the NHS. I ended up with a failed induction and EMCS (actually a brilliant experience, just to give a rare positive spin to that story!). The date of my induction was moved up a few times, but I was always consulted and could've said no at any time. I was offered induction or ELCS on the day due to the size of the baby, when I said I'd rather try the induction they were completely supportive.
The NHS pregnancy website is actually very good with comprehensive information about the appointments and tests offered. I'd recommend you have a good read of it so you know what you're comfortable with and why. But please don't dismiss anything out of hand, weigh up the information.
You should also research what services are available in your area. Don't rule out a MLU if you have one, they're brilliant for straight forward births.
But you don't need to do any of this today or tomorrow. Go to the GP, get referred to the midwives. Unless you have health conditions, it'll be a very straight forward appointment.