i get bits and bobs ‘flare up’ on occasion, frequently due to a lack of sleep or over exercise. i rest and they are gone. this is part of life, even for those not labouring under the MS badge.
however, those symptoms which persist or progressively get worse over a course of several days, are something more significant that a temporary moment of being worn down physically / mentally and could thus be attributed to a MS source ‘relapse’.
Symptoms can be mild or severe, but i think the best measure of ‘how much they are disease related’ comes down to their duration for a single occurence.
good luck, rest up and try not to worry.