Yes they are 2 separate terms; the Soviet Union was Communist and Totalitarian but the Totalitarian part even is there immediately or follows very soon because that is the nature of Communism.
The numerous Socialist governments in Western Europe all managed to avoid becoming Communist - the facts stare in you in the face. It's absolutely utter twaddle that they are the same thing. Ah but deniers would say they weren't true socialists or were social democrats - well tell them that or attend their political meetings. On a technical level this may be true but what is understood by the general population to be socialism is perfectly acceptable to many in Europe, whereas communism is always looked on as extreme. Traditionally West European communist parties looked to the Soviet Union for support, something that the socialist parties however the media and the intelligence services (who have several times tried to bring down a Labour government) most certainly have not.
Besides which when the UK had British Airways, British Leyland, British Petroleum, British Telecom, British Steel etc. a right wing government did nothing to remove them. It was not until Thatcher came along that there industries were privatised and then again not universally successfully and virtually destroyed the industrial base of the country to become a not very balanced service economy. France is more naturally socialist than the UK but never turned to communism although as I mentioned that party did have strong support
In the late 70s and early 80s the Labour Party in the UK already very Socialist became infected with a Trotskyist group called Militant Tendency who were eventually purged. Now history is repeating itself and a lot of this group have rejoined and have inspired a similar group called Momentum - unless the Conservatives make the stupid mistake of entirely abandoning the centre ground this should ensure they stay in power for at the very least the next decade until the cancer of this extreme group is removed or a new party fills the void.
Whilst you could hardly call the Blair government socialist nevertheless it did have the socialist policy of tax credits which despite having just won the election the Conservatives faced such outcry that they reversed their policy of cutting them.
When Communism fell in Russia a few people did decide to take more than there fair share leaving them ultimately with Putin's increasingly right-wing dictatorship so make of that what you will.