HCG 90- a day before my expected missed period

My period is due on Sat. My boobs have been sore for about 2 weeks. I decided to test early on Wed. and Thurs. and got the positive urine tests on regular and early result tests. I got the blood test today, and it was 90. The nurse for my dr wants to retest on Tuesday. She said it was a low level, but it is not super surprising since the day for my expected period is Saturday. Do I need to be concerned about this level? Should I allow myself to be excited?

I had a blighted ovum last time (hcg only got up to 13). I don't want to get my hopes up if there isn't much hope.