It's been a long time since I've worked on my mod because of this problem, probably over a year, so I'll do my best to remember what happened as accurately as possible. If you need clarification to help me, I can always take a look.

But, if I remember correctly I was creating an MCM menu for my mod. It all worked just fine, but my MCM menu is quite extensive. So at one point I tried to add another option and I couldn't add any more. I don't quite recall what exactly happened, but I think it couldn't compile anymore or something. Anyway, I still want to add new things to the MCM menu. So, what do I do now?

Were you using the text editor that is a part of CK? If so, then the problem might be that your script is too long. The text editor has a character limit, which I have also had issues with in the past when I was working on a menu for one of my mods. You can bypass that character limit by editing your script in an external text editor (Sublime Text, Notepad++, etc.) and compiling the script outside of CK. I maintain the https://github.com/Kapiainen/SublimePapyrus package for Sublime Text 2 and 3, but the http://www.creationkit.com/Category:Papyrus has articles with information on setting up other text editors for scripting as well.