I’m not an expert but I have just put a post on this site about something bothering me and feel like it’s be nice to know somebody cares… so I wanted to reply in case it’s of some help to you.
I would say that the best and only thing you can do is to go to the doctors and speak to them to see if they can investigate and check that you are in good health. It may be a daunting prospect but it’s the only way to calm your worries. In the worst case scenario, and you have got ill, then you will be offered the right medical care and treatment. I am sorry you have learnt that your boyfriend has deceived you in this way. He probably has little control over his addiction though it doesn’t make it any easier on the people closest to him (such as yourself) and the harmful effects on everyone that drug use can have. Best wishes.