I played the clarinet for years and have a few further ideas on your problem...
- You may be biting the reed, which would cause damage, especially if your reed end is not in the correct spot. You probably need to position the mouthpiece a little further in your mouth.
- Sometimes the end of the reed warps a little, due to getting wet and drying repeatedly. Try holding the reed in your mouth for a minute before you put it on the mouthpiece. Then, if you can find a small mirror that's a little bigger than the reed, place the damp reed on the mirror. Place the reed with the flat side down. Lightly press the reed to remove excess moisture: place your finger on the bottom of the triangular shaped cut portion and pull your finger towards the tip of the reed. Make sure not to press too roughly. Hold down a second or two on the end. That should help reduce the warping some.
- Practice and experience will reduce the amount of reeds you use and they will start lasting longer.