I know that a strong 8th house in the natal chart can indicate a sudden change in life. But what about the progressed chart? Does it signify that the time for a promient change is coming or what else it could mean in my case?
Please share your thoughts about my circumstance.
Welcome, vitohao12. 
You already have an 8th house Stellium in your Natal. Progressed Charts are useful to see what's coming up to your Natal.
I think Prog.Venus is conjunct Natal Mercury by exact or separating within seconds (I couldn't see the degrees clearly) both in 8th Cancer. So maybe family stuff has come up recently, or thoughts could be fearful or transformative new ways of thinking/communicating (Mercury) about what you want (Venus) with relation to your emotions (Cancer) or a relationship with a woman or mother figure (Cancer) or relationships generally (Venus in Cancer).
The best place to start when you're new to astrology, is to invest in a natal chart reading by a professional astrologer. You've got to learn and understand your chart 1st before jumping into, transits, progressions, solar returns, solar arcs etc etc.
I've tried to answer your specific question, but even with that's only part of the story. For example, you have two Grand Trines in your natal that may very well tell a complementary story.
Start with a natal chart reading.
Elsa's readings are amazing!
Thank Osiris Wife for your thoughts and your advice also!
Yup, you predicted correctly about my current situation: it's all about family stuff that I had a serious talk or even an argument with my mother recently.
Hope you have a nice day!