Both of sides of my parents come from Colombia, SA but originally came from Spain. I converted (halachically) but I want to know if I was jewish all along. I have searched the website www.sephardim.org where there is a list of many sephardic names (especially to those who don’t even know they are jewish). I have names like Cubillos, Romero, Tirado,Mata de la Mora. I want to know how I can find out if I have jewish in me and would I be able to marry a cohen then?

It would be almost impossible for you to ascertain that you were in fact halachically Jewish before your conversion. Even if you found out that you have Jewish blood and a Jewish name, it could have been through intermarriage, and it would probably not be feasable to find testimony that your history is Jewish all the way. On the other hand, it may be likely that you have and can find that you have some Jewish blodline. The status of convert, though one which has limitations (such as not marrying a Cohen) is one which should be treated with much honor and respect. I hope that you will realize the before HaShem you are truly chosen, and that you represent the flow of souls who were lost to our people for many years and our returning before the coming of the final redemption.