Been pooping weird and have right lower pain occasionally! Help?

Since I was a kid ive always had random periods that I'd get constipated. But at the beginning of this year, I started pooping weird. Like the only way I can describe it is like bunny poop or pebbles it's like my poop can't stay in contact with itself. And 6 months later, or 2 days ago I got pain in my lower right side until I went to the restroom. I'm really scared of what it could be and I've been driving myself crazy over it! I'm 18 years old. Could something be really wrong?