Any anti depressant medication should not be taken without advice by a specialist even if available over the counter (which may be possible only illegally). Consult a psychiatrist to confirm the diagnosis and to understand as to why are you suffering from such symptoms and then only start the treatment as prescribed. Anti depressant medicines also have some side effects and psychiatrist will weigh the risk benefit ratio before prescribing you any drug as required. Also these drugs need to be taken constantly for some time to have their optimal effect, taking them only at times as and when symptoms occur might be of no use.