Hmm so you normally only have a short cycle then?
Coule be implantation bleeding but seems to early depending on when u ovulated.
Are you sure that you have ovulated? Because eggwhite CM is a sign of ovulation and normlly I used to find I would O a day or 2 after the EWCM. Your temp drop would also be an indication of O if it raises 2moro and stays high for more than 3 days. I would BD just in case you havent ovulated.
Hope this helps.