Can someone with no earlier symptoms of tb get tb meningitis & go unconscious all of sudden just after having severe headache for few days?

Unlikely: Mycobacterium tuberculosis is spread by inhaling respiratory particles from an infected person. Tb is a slow-growing bacteria, taking months or years to cause infection. It is possible but very rare for TB to cause disseminated infection (like tuberculous meningitis) without first causing pulmonary (like shortness of breath) or constitutional symptoms (like weight loss or night sweats). Take care!