As it stands it is impossible to say what can happen. Plagiarism is a serious thing but there are places where copied text is less detrimental and there are places where it is definitely so. If your self-plagiarized parts are in, for example methods descriptions where you are describing similar or in fact the same procedure or method, the issue may not be critical, not good either. So you need to assess, or perhaps better, let someone else assess the case. Why don't you contact the person(s) running the class you mention and ask them for advise with your papers at hand?
As for retraction, I am not sure the journal will necessarily retract your papers. Retraction is usually reserve for very serious cases of fraud. I suggest you carefully look at some of the cases written up on the Committee on Publication Ethics (COPE). COPE is for editors and publishers but their cases may give you an idea of how your cases stands vis-à-vis their published cases.
So, try to get some more experienced people to look at your material and provide feedback. This will provide you with a better perspective than what can be achieved through this site since any answer here will be speculation or hypothetical since we have not seen the publications. Once you have a better perspective from your peers, and your case seem to lean towards there being a serious issue, you can consider contacting editors to hear their view. It is of course not impossible to contact them right away but right now it is not possible to evaluate if this is necessary.