Of course, the above ^^^^ is the official answer. Anything else would be a crackpot conspiracy theory, right?
I have noticed, anecdotally, that I too get colds and/or flu after I get the flu shot ... for many years. It's uncanny. The last two years, I refused the flu shot stating allergic type reactions. I have not had a cold since. Masses of people all around have colds and flu - but not me!
This anecdotal evidence extends to my colleagues at the prison hospital where I work. Those who refuse the shot stay healthy. Those who get the shot get colds or flu within 2-7 days after. My professional assessment is that the flu shot weakens immune systems and leads to real infection of real pathogens. My responses were not just histamine responses to the shot itself - they were full blown nasty azz infections that knocked me down. We nurses have collectively agreed on this phenomenon, anecdotal as it may be.
But the way the vaccine is developed is by using the organisms from previous flu seasons. This year's guess missed the mark, and I have near zero confidence in the entire process overall. Vaccinating for a known and well defined organism would change my skepticism completely.