You could still be pregnant. 10 days past ovulation is too early to test in most cases (if you are even 10 days past ovulation, you may have ovulated later than you thought). I had a very faint second line on first response at 15 dpo (the day after I expected my period). I doubt I would have seen a thing if I had tested sooner, the line was so faint then.
Early pregnancy symptoms and PMS symptoms are pretty much the same, so it can mess with your mind a bit. I did notice the cycle I got pregnant, I had 1 day of period-like cramps way before my period was due (about a week early). Other than my late period, that was really the only unusual thing I experienced early on.
The best bet is to test once your period is late.