Marx himself defined Communism/Socialism as the antithesis which requires the thesis of Capitalism to be created.

"What we have to deal with here is a communist society, not as it has developed on its own foundations, but on the contrary, just as it emerges from capitalist society: which is thus in every respect still stamped with the birthmarks of the old society from whose womb it emerges." -Karl Marx

Furthermore one of those is my statement, and one is a quote from Karl Marx, so even IF the two quotes were exclusive (they are not) it still would not be "my own contradiction" because one is a statement made by another person.