Brake Issues for 99 Malibu 2.4L

So I'm hunting ideas until I get a weekend from work. My current issue is my brake pedal will go in all the way. Before it started, it was fine but then after some time I lost most of the braking other than a little with the pedal pushed all the way.

The next day the pedal seemed to be back to where it was and has alright travel, but will have to double check.

I don't believe there was air sucked because my reservoir was atleast half way full or a little more.

There so far hasn't been any work to calipers or anything to do with the hydraulic system of the brakes.


Any suggestions of what could be the issue?