I went to a guitar shop yesterday to buy a new set of strings and had them replace my old ones. The guitar sounds fine like the usual eadgbe sound but when I tried tuning it to drop d using a guitar tuner, i noticed the tune of the strings were like c sharp d sharp etc. (I forgot the others) I tuned it to eadgbe and it doesnt sound right. Any alternative ways to get it back in tune? help.