Brake related question!

[PugLover]

Hello all,

I have a feeling that my brake pedal is harder than it was before. This happened recently and when I press the brake pedal, the pedal itself make a kind of noise as well. There is no noise coming from the wheels when I apply brake. Today I checked the brake hydraulic level and I realized that it is above maximum level. When I opened the cap, I could easily see the fluid inside. However, I remember that I could see the filter like sieve there but the fluid now is about the filter. My front discs are quite new(about a year ago) but not rear ones. Brake pads are similar. So they are not replaced recently.

I am thinking to replace rear ones but if the problem is worn brake pads and discs, the fluid level would decrease not increase right?
Can you comment on this problem? What needs to be done? Thank you.