Huge gap between posts and sidebar

Hello, I switched to comicpress recently, and made the changes I needed until I was satisfied. Now, I decided to check back, and a huge gap between the posts and the right sidebar appeared, it’s full of nothing and if for some reason, a posts exceeds its limitations, it doesn’t use the big space between it and the side bar, and I don’t know how to restore it.
I’m willing to go to factory settings and start over, but I can’t find a way to erase all the changes I made. I remember trying to find a way to make the posts area wider, but I couldn’t figure out how and left it for pending, now I have that space, but it’s unused, and I don’t know what changed, because last time I saw it it was ok, and I haven’t changed anything, so I can’t pinpoint the issue.
If you have an idea of what could it be or how to reset the theme settings to default; I would really appreciate your help.
Thanks for your time.