Can the Mexican flu make you the last person on Earth?

Possibly, if it mutates, the problem is no one can explain how it mutated into present form, I'd say 50/50 odds it was a successful weaponization of teh combined viruses that was accidentally released before it was ready. HOWEVER if people fail to complete their antibiotic treatments, as so often happens, they will breed a antibiotic resistant strain that could be a repeat of the 1918 epidemic. One coincidence to keep in mind, is for unexplained reasons epidemics happen during severe solar sunspot minimum cycles as at present. Another is, that like the 1918 epidemic, it targets those not normally at risk, and there is some thought the "black death" was actually influenza, and descendants of those who were infected and survived, have some natural immunity. Time will tell, but yes, you could be the last person left alive, if you live in a germ free environment, but the virus will mutate to find a new host eventually. there is even speculation that a virus may be involved in prehistoric extinctions as well.