Does amoxicillin help catching viruses as it kills your defences as well as bacteria?

No: Antibiotics are ineffective against viruses and because of multiple potential risks involve with their use should not be taken unless clearly necessary.

Abx don't hurt defns: Taking a well selected antibiotic does nothing to hurt body defenses. It can transiently alter the balance of bacteria in the intestines & alter the existing balance on some body surfaces, but it does not remove any resistance you have to viruses. Your viral response system works alongside your response to bacteria, but essentially ignores antibiotics.The gut bacteria are easily replenished.