What exactly do you mean? If you mean that you know you ovulated and AT THE TIME of ovulation, you had some blood, it's normal, and not a sign of pregnancy. If you meant a week or later after you know you ovulated, you may be pregnant.
During your period it is normal to experience blood clots but if you mean when you go to the bathroom and are not on your period, then this is not normal and should be investigated. It is most likely caused by a hormonal inbalance.
It is possible to experience vaginal bleeding when you are pregnant, but it is unlikely - it is also biologically impossible to menstruate during pregnancy. If you think that you could be pregnant then take a pregnancy test to determine if you are pregnant or not.