What happened on your pills?
From what I have heard (and carifairy can give better info) a surgical abortion like the kind you will most likely be getting at this stage of pregnancy can feel like several things. There are a couple of anethesia options, one where you stay fully awake, but are sedated slightly by medicines, and another way where you are fully unconscious. If you are conscious, cramping is the most common feeling, like moderate to severe period cramping. You may feel sore afterwards, and you'll normally be taken to a recovery room to get your strength back.
Afterwards, period-like bleeding will continue for a couple of weeks, sometime longer sometimes shorter.