Missed period, negative pregnancy tests

My husband and I have been trying to have a baby so I have been taking clomid and prenatal vitamins for over a month now and even missed my period but after taking almost 5 pregnancy tests by different brands they are all coming out negative. I’m not sure if the prenatal vitamins or the clomid might have thrown my body off course or changed my cycle but I have set an appointment to see my doctor next week. Has anyone experienced this before?