All right, so to start off, I'm really sorry to hear about your problems. The upside (no, this isn't the right word but meh..) is that the issue you have described is fairly common. I'm only in year nine but I also used to get home and more or less study until bed time. However, I have discovered something far more effective for both study and relationships; taking breaks and setting time limits and plans.
I used to do:
Get home at 4;30
Eat/chat with my parents until 4:45
Study until dinner (~6:30)
Eat dinner
Resume study at 6:45
Start the bed/shower process at 8:15
And trust me, it got tiring. Espiccially tiring was that one of my parents kept having anger moments about my (not very significant) 'rudeness'. Honestly, I think I was just getting too tired cos of all the arguments and overstudy. But anyway, I figured that that obviously wasn't going to work so changed my schedule a little bit
Get home at 4:30
Eat/chat with my parents until 4:50 (I know it's only an extra 5 minutes, but it adds up)
Study from 4:50 - 5:30
Go for a jog
Study from 5:50 - 6:30
Dinner and chat with parents (6:30 - 7:00)
Study 6:45 - 7:20
Chat to parents or relax for 10-15 mins
Study 7:35 - 8:00
Chat to parents/chill
Read book
Go to bed etc.
So although it may seem a bit weird that I'm describing my schedule to you, I'm dong it for a reason; I'm trying to illustrate that taking an extra couple of minutes to relax and "smell the roses" can have a big benefit. It means that friction between my parents and I arises much less often and I can concentrate better when I study. Also, try and cut out computer gaming and excessive television.
Also, the fact the your parents are talking to you about things like the fact that are not smiling as much as you used to indicated that they do have your best interests in mind, although I'm sure it may seem like the opposite.
So basically what I'm trying to say is take a few breaks - both for academic and emotional/social reasons. Talk to your parents and try and maintain a positive relationship, however hard it seems.
P.S. I don't agree with the fact that "good grades don't mean anything at all" I do think that they
CERTAINLY aren't everything. I mean, why do you really need amazing grades? Answer: to get into ________ (I'm guessing). But there's always another way in. But don't let that make you think you shouldn't give VCE your best shot, just don't let yourself get too stressed etc.
In terms of motivation, maybe have a look at this thread:
Motivation Issues - HELP!!! or
Motivation and keep in mind that VCE is a totally awesome experience - in terms of education, you are in one, if not the best country in the world, being given a wide range f subjects to chose from and being able to learn so much awesome stuff. View every opportunity to learn as an opportunity to better understand the world you live in and
ADVANCE HUMANITY (if that's what floats your boat lel.)
Hope I helped
