Hi there ~
I understand your concerns. If you did a very small amount of MDMA over the weekend and regret it, it probably means that you did not like it and do not want to do it again. I hope this is the case as MDMA may be life threatening. I also believe that you may become dependent on it if you use it long term to treat any psychological issues you may have. Please consult a psychiatrist
who specializes in the use of substance use disorders. I hope you do so as soon as possible.
I hope this helps. Take care and have a lovely day!