In common usage, "I'm fine" is a generally positive way of saying "There's nothing particularly wrong"; yet it also means that there isn't anything superlatively right, well, or good.
"I'm good", however, is a positive assertion that your personal situation and the events surrounding it are supererogatory compared to your usual state of being. That is, by describing your state of being as "good", you suggest that your personal situation is definitively satisfactory, in all respects.
Basically, "I'm fine" means "I'm OK", "I'm getting by with no problems", and so on, while "I'm good" suggests "I'm happy", "I am currently aware of how well I am, and how well my life is going", "I'm satisfied, content, and am quite enjoying myself", etc.
You can think of it this way:
"Are you sick? You look pale, and weak."
"No, I'm fine! Please, stop worrying about me!"
versus:
"Are you sick? You look pale, and weak."
"No, I'm good! I've actually been working out indoors, recently, and I may be pale, but I'm certainly not weak. I feel great!"
Best Answer
"I'm glad it helped" is grammatically correct. But it doesn't mean that you're glad you helped, it means you're glad that something helped. It might, from context, be clear that it was something you said, did, or gave them. But "I'm glad it helped" alone doesn't say that.
You can say "I'm glad I helped" or "I'm glad I was able to help" to indicate what you want. But you can't say "I'm glad it helped" unless it's clear what it is you are referring to -- some specific thing that helped.