Hearing problems, tinnitus?

OK i bought a pair of cheap iems that get really loud so i was listening to them at 75% on my ipod clic, which is the same level i play my shure srh840 at. and now my ears have been ringing excessively for 30 hours. i have read on the internet that this is only temporary and should clear up after a few days. should i worry. this is seriously making me rethink using iems. one more thing i can't listen to my headphones because they all sound terrible now. this has happened before and its always cleared up but i am worried my ears might be seriously damaged. btw i was listening for 1.5 hours at work at 75% volume if that means anything.