I wish I had some money...

I'm curious, I never understood fully volume vs share price. I've been trading and investing for years and thought I had a pretty good understanding, but can someone clarify the below?

From December to February, it took over 10 million shares traded on the way up to bring the price from 10 cents to 30 cents, now it only took couple million shares traded on the way down in the past few weeks to bring it almost all the way back.. I know that happens all the time, just curious if someone can put it in plain English why one fifth the amount of shares can have as much of an impact.. what gives?