My period is five days late, but I took a

Patient: My period is five days late, but I took a pregnancy test and it came back negative. Usually my period is on time but the longest my cycle has been was 31 days. I took 1000mg of vitamin C to try and induce my period but it has not come yet. Is there anything else I should do? I have prom in two days and was hoping to get it before then.

Doctor: