SR,
i am not really sure about which gives you higher salary, science(env) vs pharmaceutical science
but i heard that there's more demand for pharmaceutical science graduates.
So decide yourself. Live your live as it is. Family problems, well they comes and goes.
But you got to live your own life one day. Live your own life, choose your own career that you love.
"When you love what you do you'll never have to work a day in your life"

Take me for example, my family wanted me to study engineering, medicine or something that was constructive. Guess what?
I choose to study people, places and history. Well i may regret someday, somehow, i am absolutely sure this was my passion. I won't regret when i am about to die that i did what i wanted to do and not control by others decision.
Maybe one day i might be able to contribute an important aspects from Nepali archaeological and anthropological side.

Look on a bright side.
 cheers,
            jpg