Well well well, look who's back with a tech question. It seems that even with all the advances in mining technology, problems still arise. There could be many reasons for your drop in hash rate - an unstable internet connection, issues with your miner hardware or maybe because you forgot to feed your hamster who runs on the wheel and creates electricity for you 😄. Sorry, just kidding about the last one! Have you tried restarting and checking all cables? If that doesn't help I suggest calling your friendly neighborhood IT guy or gal!