Yeah, I would definitely test if I were you. You should not count that discharge as your period. Some woman get that discharge and it is chalked up to being implantation bleeding. But that is not always the case. Just trying to prepare you.
Even though you are late already and it really shouldn't matter. I still suggest that when you take the test you take it first thing in the morning with your fmu (first morning urine). This is not necessary. Just a suggestion.
Did you have unprotected sex?