I am sorry to hear what you are going through. I think you've already been given some great feedback from others. I would only add that jealousy is one of the more powerful of human emotions and it gets especially messy. My sense is that the boyfriend found out about your "I love you's" and close relationship and through jealousy told your friend to cut you off immediately. If he happens to have a powerful personality or is a controlling narcissist, then you would have been a huge threat to him because you can provide something for her that he can't via the pure heart of an empath. Jealousy is elevated based on threat. And quite obviously you were a huge threat to him as he thought you were trying to take his girl. I'm quite sure something big went down with the two of them on this topic and she just followed his requirement to cut you off. As much as that must hurt, I would not blame her. And definitely do not blame yourself. You did nothing wrong.
As for your heart, we've all been broken up with or have been dumped by lovers and friends. It hurts like a knife to the heart. It is especially hard for you as an empath because you feel so strongly. Just know that time heals all wounds. I'm quite sure your friend will miss you and try to reconnect with you at some point in the future. But in the meantime you need to focus on protecting and taking care of yourself. One of the greatest faults of being an empath is that we feel so deeply that when something upsetting happens we obsess over it and literally beat ourselves up over it over and over again. You have to recognize that and find a way to heal and move on.
You said you suffer from depression and suicidal thoughts. Being depressed is such a common human condition in our society these days that it is very easy for a doctor to diagnose that. However, it is also important to try to find out how much of that condition is caused from you being an empath. Are you overloaded up by all the stuff you pick up from people every day? If you are, this can often manifest as depression. And if it builds up long enough then unfortunately suicidal thoughts can present when you feel spent and helpless.
I would suggest you keep on schedule with what your doctor is recommending for the depression. And then separately try to work on a daily grounding regimen to help you through these tough times. It is critical for us empaths to practice grounding to release the buildup of low energy that we pick up every day. Think of it like a plugged sink filling up with water. At some point you need to unplug and drain the sink or else it will overflow and create a mess. Being an empath is just like that. We need to ground often to allow that low energy to pass or drain out of us. Doing so correctly will give you an almost instant boost in energy and elevated mood.
If you need any help or tips on grounding please let me know. And in the meantime, try to work on being positive. Do things that make you happy and work on surrounding yourself with positive people so that you can heal yourself. You will survive this. When I look back on my life experiences so far, the toughest times presented the greatest lessons. This has especially been the case with regard to my empathy. I have learned to eventually convert every “bad” experience into a lesson that I can use to come away stronger as time passes. I hope you can learn to do the same so that you can strengthen yourself from the inside. I know it is really hard to see a lesson while going through pain. But there is a lesson in everything we experience.