You cannot reduce your stop-loss level to expand your position; otherwise, you will be unable to withstand normal fluctuations, leading to frequent stop-losses.
How to deal with excessively large losses in a particular variety
When you experience significant losses in a certain variety, you develop a sense of aversion or even fear towards that variety. Most people choose to give up and no longer trade that variety. In fact, this is a wrong approach. The correct approach is 'not to abandon, not to give up' - 'if a sheep is lost, you must look for it among the flock'!