the high e-string on my strat broke and i wouldn't like to replace it with a random one so i'll have to buy some strings on monday. will it cause any abnormalities if i leave it unstrung till then or should i use a random string?

1x string isnt a big deal.
If you remove all and let it that way for a period of time, expect your neck to curve.

It is very simple - just downtune your guitar out of tune, and on Monday replace the string. I tend to replace all 6 of my strings when one brakes, but just downtune the guitar