You feel guilty because you love your family, simple as that. That's not something you can change and there's nothing wrong with it.
Family is one of the strongest bond a human can experience. Of course, some people don't care because they've been treated horribly by their families.
Maybe suicide is easier for them, but - luckily or unluckily - it seems neither of us belong to that group.
I can't be sure, but I honestly doubt that your family would be better off without you. These thoughts are often the product of depression, I've experienced them myself, but I realized that they're not the truth, at least not in my case.
If you're anything like me, your rational part tells you that ending it all is the most logic thing to do, while your emotional part is tormented with guilt for wanting to leave your loved ones behind.
Welcome to the community, you're not the only one feeling like this.