Hi and welcome to HCM.
False positive results are possible but uncommon. Unfortunately in many cases the right mechanism of transmission is never found. Your dietary and lifestyle habbits arent related to hep transmission. It can be tranmitted by sexual intercourse, by contaminated personal items such as razors or nail care equipment,by contaminated needles, bites etc. It could have happen at any age. Virus could have been inactive for so many years. The more importatnt now is to evaluate your liver damage
which isnt serious because you would have more intensivef symptoms and findings. I recommend do follow hepatic diet and avoid alcohol. There are some medicines too but it isnt necesarry in this stage. WIsh you good health.