(((((((((((((((hugs))))))))))))))))))))
I'm sorry your mother isn't supportive. My family really isn't either, they're just going along with whatever I do now because I told them that their permission or blessing to go into counselling (and then take antidepressants) was NOT needed. It was a good decision for ME and they had no right to boss me around.
As for "only needing God" ... bah... I hate that phrase. I like what was said earlier, because I believe that to be true. God (or whatever higher being you believe in) helps those who help themselves.
I'm sorry your mother isn't realizing how much she's hurting you (and your sisters) by not being supportive of this. Some people are like that unfortunately.
Perhaps eventually your mother will come around and realize you're performing self-care and that this is for your benefit... if she doesn't, sadly that's her decision because it sounds like she may have some issues she needs to work through herself.
I wish you the very best in your counselling, and I hope your sisters make decisions to seek help for themselves, and that they are not dissuaded by your mother.