Yep, you have testosterone to thank.
Due to hormonal changes, your larynx (voice box) and vocal folds are going through a dramatic vocal transition.
It's like leaving a piano in the rain, one second it's swollen, the next it's cracking and thin.

But please, don't be like so many others that give up singing just because they don't like how they sound during their voice change.
You will need to gain a new understanding of your voice.
Luckily, vocal training through the pubertal change can dramatically improve your ability to sing through this hard time.

My advice is to work with somebody who really knows what they're doing so they can help you choose appropriate songs and keys no matter what your voice is doing that day.

But here are a couple of things to keep in mind as you approach singing:
1. Be aware the your range will change daily–Again, due to the influence of hormone, your voice will thicken or thin more on any specific day and there will be little you can do to change this. Go with the flow, allow the voice to rest where it does and sing the best you can.

2. The place where your chest and head voice connect, called the bridge or passagio, will also change–We hear this all the time when the voice “flips” or disconnects to “falsetto“. In time, this place of transition will become more stable also, but only with the correct vocal instruction.

3. The most important thing to maintain in a transitioning voice is a sense of bottom and top, which correlates to thickening and stretching of the vocal cords–Since young people’s voices are transitioning to a larger, thicker instrument, making sure that the student is stretching their voice into the head register (even if it’s falsetto) is better than avoiding that area altogether. This is something I see in lots of young people. “I don’t sing high notes well, so I don’t sing songs with high notes”. This is why it’s so important that the voice teacher helps the student sing through their entire range, or else this fear of high notes will become a real inability to sing them.