I was supposed to ovulate on march 9th, I had sex on the 7th and the 10th, on the 14th I had some spotting and have been very nausea for the past couple of days, my breast have been sore but I took a pregnancy test and could see a line trying to appear but didn't quite come up, could I be pregnant?

It would be very early, but some women do get a positive as early as 8-10 dpo. Best to wait and see what happens when you would expect your period, or at least a few days before that time, and test again if necessary.

When you do test again, be sure to follow the directions exactly, especially in regard to the time frame for reading the results. If you look at it afterwards, it can sometimes look like a faint positive, but it is only accurate if it comes up within the time stated on the test. Good luck!