That sounds like a really difficult situation. I'm so sorry about your lack of insurance, I can imagine that makes the decision extra difficult.
Here are a few suggestions that will hopefully be helpful.
One, I think it is really wise to remove yourself from a situation if you feel a blow up of emotions starting to happen. If you're in public, even just excusing yourself to go to the bathroom can give you some of the space you need to feel your emotions and let them flow through you. For me personally, my feelings tend to come on very strong and very fast, but I also calm down soon after, almost like it never happened. So if I can remove myself when I'm at my worst, I can avoid lashing out and hurting others. Remember that the worst you are feeling in the moment won't last forever.
Two, once your feelings do subside, try and come back and explain how you were feeling to your boyfriend. If you explain why you got upset and what you're nervous about, that can help him understand why you react the way you do and will hopefully avoid the two of you hurting each other in the future. If he is aware of your condition and you help explain it to him, he will better be able to help you get through those difficult emotions
Finally, try to keep some small physical object you can squeeze or play with when you're getting stressed, especially if you know you're going to be in a difficult situation like a family gathering. Even something simple like a smooth rock in your purse or your pocket you can rub with your fingers or squeeze very very hard when a sudden wave of emotion comes on. In a emergency if you don't have anything, you can squeeze your hand very hard, dig your fingers into your palm, and take three deep breaths in and out.
So, my small advice is try to remove yourself in the moment, make sure to explain your feelings to your boyfriend, and use small objects and deep breathing to catch yourself in the moment. These are just some very basic ideas, but hopefully they will be helpful. If you have any more specific or long-term questions, feel free to message me directly. I will also say, for me personally, being medicated has definitely been worth it for me. But I hope you'll be able to find the help you need even if being medicated isn't an option for you right now. Best of luck friend