To be sure what condition your brakes are in, you will need to have a
look.  You can usually look at the rotor surface (disc) and get some idea
of the overall surface condition.  And you can usually see the brake pads
well enough, without pulling the caliper,  to estimate how much friction
material you have left.

Warpage or uneven wear of the rotor may be what you are feeling,
and if this is the case, you will have to have them machined true, or
replaced, to return them to normal braking condition.

Brakes are too important to guess about.  Have someone competent have
a look.  Find a good shop, not just a brake franchise or a dealership,
that will be honest enough to give you an unbiased opinion, and which
can do the work properly and at a fair price if you need repairs.