Ttc And Very Anxious! Could I Be Pregnant

This is my first month ttc and I am anxious .. Well .. Dying .. To know if i'm pregnant. What makes it hard is that my period is kind of irregular, but usually, my cycle is around 38 days. Using that as a standard for calculating my ovulation date (and I did test using an ovulation kit on 9/10 .. It showed a faint line. I didn't test after that .. Don't ask me why ..), my ovulation should be around the 12th. So, I had intercourse on 9/11 and again on 9/14. Then, starting on the 16th (so only about 4 dpo), I began spotting. It lasted for 5 days .. It was light enough that I didn't need a pad .. Just a pantyliner .. And it was brown in color. Do you think this could be implantation bleeding? I have no other symptoms of pregnancy, however. So .. If my ovulation really was the 12th, then my period should be starting 9/26 .. I tried testing twice out of anxiety .. But I think it was way too early, so it both came out negative. What do you think my chances are that I might be pregnant? I don't normally get any spottings .. Maybe like twice in my life (i'm 30) .. But then, I have been pretty stressed out .. So I wonder if maybe the spotting is stress-related. Any comments or answers would be greatly appreciated. Thanks!! :d