Really appreciate your feedback Sir! First 2 tips are really essential for a beginner like me. I have a decent guitar and cables, also some experience in building the signal chain, so I guess it's all about stop using cabinet emulations with a real cab and start using a preamp instead of "full amp" just like you've mentioned. It was all good when I was practicing at low volume with my 30watt combo amp, now I know the reason why... Anyways, I'll have another rehearsal in a week and see if the problem is fixed!