Fares often seem to go up for the weekend, and then back down during the middle of the next week. It is a mostly a function of the fares in the lower rate buckets getting sold and then replaced, although it can also be rate changes. You don't mention what the fare class was for the different rates.

Not really time to panic yet. Maybe you could set some alerts. They send you an email when fares drop.

These systems have alert functions:

Kayak
FareCompare
Southwest
Yapta
TripAdvisor
Travelocity
Expedia
Orbitz

I'm sure there are others, but 3 or 4 of these is enough. If you get frustrated with one, just move on to a different one.

I think you want to buy your ticket at least 2 months ahead, but don't get stampeded into moving too quickly.

Romelle