I took a plan b, is this normal?

I took a plan B pill and it made me get my period like 2 weeks early (august 1st-5) but everyday since then ive had to wear pantyliners because i have dark brownish spotting with lots of super tiny dark chunks. There seems to be less and less spotting eachday but ive never taken plan b so dont know if this is normal. What do u think?