Battling bigger people can suck. But it can also be a great learning experience. More on that later. This post is about why you shouldn't get discouraged about the suck.
One thing that helps keep things in perspective for me is the Boyd Belt System. This means that for every twenty pounds someone has on you, it equals a belt rank. So if you're rolling with someone who outweighs you by forty pounds, it is the same as fighting someone two belt ranks higher than you. So don't get discouraged if you're not tapping people out who are bigger than you- even if you are the same rank. This doesn't mean you'll never manage to win your matches. As you get more experience things will start to level out.
We had a student in Aikido who was tiny, we had to order a child size uniform for her. Yet she always went with the biggest guy in class. I really appreciated that mentality. You can learn a lot from trying - AND - failing against bigger people.
Personally, I'm okay embracing the suck and learning what I can from having my techniques fail on bigger opponents. Someday those techniques won't fail, and that will be a gloriously awesome day.