TTC..... please help

So my husband and I have been trying to conceive for a while now. My doctor recently placed me on prenatal vitamins and folic acid. We had unprotected sex several days during my fertile days last month. This month I was experiencing what I thought to be pregnancy symptoms (nausea, frequent urination, overall tiredness), but my period came on... And it came on A WEEK EARLY!!!! This has never happened as my period is usually regular. Could I be pregnant? Has this happened to anyone else? Please share your thoughts and comments.