Help OPK? Pic..

Nova • 24 Years Old. 1 Daughter born 10.26.15
So my SO and I are TTC month #2 with my irragular cycle.. I just got off depo so everything is messed up but anyway... this is our first month with BBT and CM charting and using OPKs... yesterday my BBT dipped and today I noticed my CM is plentiful to put it lightly but more like egg whites so I'm getting excited and took an OPK which is negative but was wondering if the line gradually getting darker as u take the tests is a sign of impending ovulation..? There was no line on the 4th but there is one today just faint though. Input on using OPKs please and if this means I might get a surge soon?