No that's not heretical, but illicit and very VERY bad form.

Look I'm not trying to defend you AT ALL here. However what you did was uncommon practice in Medieval Europe. The holy sacrament of marriage is given not by a priest but by the man and woman to each other. This is how some people clandestinely married back then. However it causes a lot of scandal (like with you now, in this thread) and because witnesses cannot testify and it's not noted for by the Church has always been disavowed and quickly forbidden altogether.

So, if you both honestly gave each other vows, you are already married, you cannot even marry again this way. However money should never be an issue since a church can never ask for money for a marriage ceremony. Rings are also purely optional, just buy a cheap copper one or a regular gold one. You should repent, talk to a serious traditional priest, explain your situation, then clear it out.