Yesterday I realized my clutch pedal was acting funny, it was catching really low, when it normally catches high. It travels down really easily, but is slow when coming back up. I filled up the clutch master cylinder reservoir with DOT 3 brake fluid(it was empty before), let it sit for a while, then tried to drive around the block to see if it fixed it. Well, I'm now locked out of every gear. What went wrong? The clutch was fine a few days ago, I didn't do any burnouts or anything lol.
EDIT: I'm absolutely lost. There are no clear or specific instructions, even in the Haynes manual. Where exactly am I letting the air out from? I've tried loosening the upper and lower valves but the nuts do not budge one bit.

 

UPDATE: Goes in gear with engine off. Doesn't go in gear with it on.

 

Did you bleed the master cylinder? If not that's your problem more likely. Use search to find out how. Very easy.

 

You might have a leaking hose near the slave cylinder. Or a bad slave. Not fun to bleed.

Many of us have installed a stainless steel hose which connects the slave cylinder directly to the clutch master cylinder. Doing that by-passes all of the failure prone lines which Nissan cursed us with.

Intrusions in the stickies.