The best place to start with here is your parish priest. He can advise you on this matter.
If you are not a Catholic and you entered into a marriage outside the Catholic Church, your marriage is recognised as valid by the Catholic Church. For example, if you are a Methodist (or were at the time of your marriage) and married a Presbyterian in a civil ceremony, the Catholic Church recognises your marriage.
When you got married if you were a Catholic, did not marry in accordance with Catholic form, and had no dispensation to marry outside the Catholic Church you would have a case of defect of form.
In either scenario the Church needs to look at your previous marriage and decide what happens next. It may declare it to be invalid through defect of form by an administrative procedure. It may decide your case is more complex and needs to go through the tribunal process.
The Catholic Church will not allow you to marry in the Church until your previous marriage status is resolved. So, I would urge to go and see your parish priest. Unfortunately, you may get the answer that everything is OK. That is the wrong answer and I would urge you to contact your diocesan tribunal. That’s what they are there for and deal with so do not hesitate to contact them.