I think you are experiencing cognitive dissonance, having been taught all your life by left-wing school teachers that Hitler was a Fascist. He wasn’t: he founded the German Worker’s party, later called the National Socialist Party, and after being elected he introduced pensions, unemployment benefits, massive state work schemes and took control of the means of production and distribution: all good Socialist policies.
He then seized total control of Germany, just like Stalin did in Russia, using much the same methods — terror and secret police.
He maintained that the Second World War was being waged by the German Socialist Republic against the Capitalist Plutocracies of the West. He was an ally of Stalin till they disagreed over the partitioning of Eastern Europe.
Svetlana knows European history and will not let you get away with slogans instead of facts.
The difference between Socialism and Communism is one of degree, not of nature. Both abandon the capitalist free market and individual freedom, in favour of centrally planned economies. Central Planning doesn’t work, so inevitably Socialist economies always fail. Stalin referred to Communist Russia and its occupied territories as the Union of Soviet Socialist Republics, so apparently shared Svetlana’s assertion that the two are essentially the same. Socialist democracies are described as Socialist, Socialist totalitarian dictatorships are described as Communist, but are still Socialist, at least in rhetoric. In practice they are indistinguishable from Fascist totalitarian dictatorships. Below is an intellectual discussion of the differences between the two, but it assumes their rhetoric accurately describes their philosophy and economic theory. They don’t: the best discussion of Socialist/Communist regimes’ methods can be found in George Orwell’s classic novel 1984. You should add that to the list of reading that Svetlana has already given you.