It's awesome that you've already joined a few groups. Groups are a great way to connect with others in the community that are interested and knowledgeable about similar topics. You can pose questions, offer advice, or share news with everyone.
One of my favorite things to do here is blogging. In my blog I like to write about the newest health research I've read, add my own thoughts and analysis, and see what others think. It's great because blogs are a way to get in touch with the entire community here. Feel free to start your blog, introduce yourself, share ideas or your thoughts. I think a blogpost about Lupus would be a really valuable - and one that I'd certainly be interested in reading!