What's going on?

Nicola • Married. 29 years old. Mmc at 11 weeks July 2015 and mc at 4+3 weeks Nov 2015. Pregnant with baby girl due 30.07.17 ♡♡
On all apps and ovulation calculators apparently 30th-4th Jan is my fertile window so we bd'd last night. I now feel there's no chance as had negative opk last night and this morning. I also haven't had ewcm like I normally do? Confused and feeling down about our chances now :'( xxx