Am I Pregnant, PLEASE ANSWER??

Ok, so my last period I had was October 7th. I had the night before so it might have been possible to have conceived then but I had on October 18th, 20th, 21st, and 23rd. I tested negative on OPK's all month until today when it was positive, it had both lines, which was weird because I didn't think my ovulation could be this late. I didn't test for the last two days. I tested for pregnancy yesterday but it was negative. But I have been feeling queasy for the past week and back aches. I heard that OPK's can test for pregnancy as well. Is there a chance I am pregnant? I do want another baby, I just don't know if I am ready this soon. Either way this baby will be loved if I am. Please tell me my chances? No negativeness here please, I don't like rudeness. Also, has anyone used the OPKs and had pregnancy follow?