How to maintain a Buddhist practice through dark times?
I am in your state. I am sick as well. I want to be a monk but I can't.
The difference is I don't feel bad because I can see my effort when looking back to check what I did.
I can say I never sit  as much as you, and I can say if I can practice as much as you doing, I am going to be very happy and proud of it surely.☺
I understand the chance to meet Dhamma is extremely difficult, every practitioner doesn't want to miss this chance. However, you are trying and you still not giving up, so don't count your chickens before they hatch. 
Samatha is for happiness, Vipassana is for serious considering. Both are helping each other, but Worry is for lost.
Relax. ❤♡♥