Only had a few sips of a cocktail. got very dizzy, darker vision, felt numb or something strange. could the alcohol be too strong? normally i can drink small amounts without issues?

This is not normal. I suspect that someone may have tampered with your drink, adding a substance that would make you have these symptoms. Were you at a bar? someones home? Make sure that you are very careful when drinking in public. Always have a friend with you whom you trust to take you straight home if this happens. Never accept drinks that you have not seen made.