Is Post Coital Spotting Normal?

Had what seem to be a perios for 2days the firstday which was saturday a littler wierd light and then kind of heavy flow the second day sunday light could wear a panty linear to be exact blood was just noticble when I wiped myself and then dissaperar anan come back monday no blood just spotting if that now I have a brownish slimmyy looking spotting tuesday which is very light did have un protected sex on may 22 I just don't understand