For me I feel the same way about my family my family is great but I have always been careful not to relie on them to much. I really keep it limited on how much I tell them cuz like you I am affraid of stessing them out. Except my one brother I talk about my problems more because we are really close and also he has bipolar disorder and anxiety too. But in general I keep my support system with friends who also have mental illnesses similar to mine.
I hope you can find friends here or other places that have similar problems to be the major support system

take care