Based on my understanding of karma you will most certainly receive 'bad' karma from committing suicide, although this doesn't mean punishment. That's not how karma works. Because suicide means that you have not learnt your particular lession in this lifetime, ie: overcoming/surviving whatever hardship it is that you feel you are currently experiencing, you will have to do it over again in your next lifetime - bad karma. How this manifests exactly is anyone's guess. However, you may, for example, have a close loved one who commits suicide and you will have to face all that pain that you caused your loved ones in this lifetime.
I'm sorry to hear your so unhappy, I really believe anyone can overcome depression with the right help and mindset. Whether you will have bad karma next time around or otherwise, you have this life now, and it is precious. I really hope you can learn to enjoy it. And then you'll have an even better life in your next life!