How far are you from the Twin Cities? My sister lived in Lacrosse and ended up moving to Minneapolis because she couldn't find an apartment either. She was originally sharing a house with a bunch of people but wanted her own place.
It is a bit past the middle of the month, so only apartments that couldn't fill a room would have one left.
If you don't live in a college town, then people generally stay in them for a long time with very few openings happening at a given time.
If you do live in a college town, then they tend to fill up quickly the month that a semester starts. So you will probably have to wait till May before anything really comes up (or whatever month that most colleges in the area let out.)