I live in a condo that was renovated from an apartment. For the past couple of days the shower will not heat up enough to be comfortable when I try to take a shower in the morning. I have checked the water tank and all is well there. The bathroom sink gets hot without a problem. I finally just take a not so hot shower and continue getting ready for work. When my husband gets up and showers he has had no problems and gets fully hot water in the shower. This has just started. The shower water heated fine last week. What could be the problem?