Firstly, I do hope it is a negative test.
I had an abortion because of HG in my first pregnancy, so you're not the only person to consider this. HG is horrific and you have to think about the family that you already have.
I saw my GP a few days after the positive test, and they referred me to BPAS, who do the abortions in our area. I had a telephone consultation with them the next day, and once we were all happy I was comfortable with my decision then they gave me the options for the procedure. I chose a medical termination, as that could happen quickest. If I remember right, I saw the GP on the Monday and had the abortion on the Thursday.
They have a chat with you at the centre, to make sure you are still ok with your decision. There was no one outside the centre I went to. Then they do a scan to confirm the pregnancy, but you don't see it at all. Then they gave me the first set of tablets to terminate the pregnancy, and I had to go back 6 hours later for the second set of tablets, which start the bleeding (some people go back the next day for this).
The bleeding started late that evening. It was heavy, but nothing worse than a very bad period. You see a lot of clotting but you don't see the embryo, especially if you are very early on. The bleeding lasted on and off, and not especially heavy, for the better part of a week.
It would help if your partner could take a day or two off work to support you. Even if you are certain about your decision it is still a very hormonal time and you might be upset. Plus you will probably be tired for a few days, and also I found that the antibiotics they gave me afterwards made my stomach feel quite poorly for a few days.
However, while obviously I wish I never had to go through this experience, it wasn't terrible and we knew we were doing the right thing for our family. There should be plenty of counselling available too to help you if you need to talk. I found the whole experience with my GP and the clinic very calm and non-judgmental.
Good luck. Please do ask anything else you want to if you do get a positive test.