How do I stop my stomach ache problem?

For about a week or 2 I've had a really bad stomach ache which is because I've got bad gas. Every time I fart it always smells like rotten eggs and I'm always on the toilet for about half an hour. I stay on it so long it causes my butt to hurt (had to mention it.) and I have to waddle about everywhere. Does anybody know how I can help my bad gas and toilet problems?