come on, lady
Don't be so scared.
It is highly probable that you have already had antibody against Hep virus. The truth is, adults are not so easily infected by HBV because their natural immune system can automatically kill the virus. Most HBV patients are infected at young.
Have your 3 children taken the HBV vaccacine already? It is required by the government (at any country). If they have, their chance of getting infected is zero.
Anyway, go have a test first.
By the way, your boyfriend should at least have asked you about your vaccine status before making love to you.
Get yourself and your close family tested - that is the only way to be sure.