I think that you'll find that once someone has the upper hand, one has a tendency to blunder. You think it is over and victory is yours, but then you hand the game right back.

So don't give up. Continue to play and wait for your opportunity.

As Perseus points out, trading two rooks for a queen can be a good for either side. I've read that if there are enough other pieces to support the queen, the queen has the upper hand. If the queen doesn't have support, the two rooks are better. Here's a game that I've played where I sac'ed my queen for two rooks and emerged the winner. I had the white pieces:

1. d4 d5 2. Ng1f3 Ng8f6 3. Nb1c3 e6 4. b3 Bf8e7 5. e3 O-O 6. Bf1d3 Nb8d7
7. O-O a6 8. e4 dxe4 9. Nc3xe4 Nf6xe4 10. Bd3xe4 f5 11. Be4d3 b6 12. Rf1e1 Nd7f6
13. Nf3g5 Qd8d6 14. Bd3c4 Nf6d5 15. Qd1e2 Be7xg5 16. Bc1xg5 h6 17. Bg5d2 b5
18. Bc4d3 Bc8d7 19. c4 Nd5f4 20. Bd2xf4 Qd6xf4 21. d5 exd5 22. cxb5 axb5
23. Bd3xb5 c6 24. Bb5xc6 Rf8e8 25. Bc6xd5 Kg8h7 26. Bd5xa8 Re8xe2
27. Re1xe2 Qf4d6 28. Re2e3 Bd7c6 29. Ba8xc6 Qd6xc6 30. a4 g5 31. a5 Qc6f6
32. Re3e1 Qf6c3 33. a6 1-0