Hi Aisha,
I can see you are distressed about your situation but do not be afraid. You are not alone and there is always support for you, especially in this forum.
Read this post by Thomas When/how to disclose hep b in a potential relationship? and Dating with High Viral load
There is great advice on communicating with your partner or potential partner.
As for when to disclose, usually, before you decide to become sexually intimate. But you can talk to them well before that if you feel comfortable with them.
In addition to telling them your diagnosis, you can ask them questions about their knowledge of Hep B such as whether they are aware of the mode of transmission of Hep B and if they are vaccinated against Hep B.
As always, practice prevention methods and take care of yourself physically and mentally. Anyone should see you for your strength and you deserve to live your life without stigma.
All the best,
Sumaya.