How can I support a loved one struggling with mental illness with I am struggling myself?

 My name is Kit ( birdsrhea) I am  bipolar, Have PTSD, social anxiety, psychotic features. I'm on a ton of meds. My son also suffers from schizo typal disorder. I'm trying to be supportive for him but I get so sad and then hyper. The mood swings just hurts our relationship. I'm constantly apologizing and he gets upset and frustrated. He won't take meds which is harder on me. As I am medically compliant...my therapy is going well. But they have to change one of  my meds now to lithium.  It is very hard trying to support another mentally ill person. While I'm suffering myself. Any advise is appreciated on how to get him to take meds. 

@Agaw82‍ Hey there. That’s a tough spot. Trying to take care of your own issues, and his and his girls too I’m sure. Is there any family around you all? That you could stay with or go to even if just for a little while if things got a little too out of control? The mama bear in me wants to tell you(for your safety)get the hell out of there. I’ve been in that very same spot. And unless he’s willing to admit he needs help and accept it, things might not get better, and possibly eventually escalate. As much as you love him, this is an abusive situation. However....I also know how very very hard it is to take that leap of your not ready to leave yet and there’s much more to it than just leaving. Remember, this is just my opinion girl. I do NOT want to upset you in any way. So just take it with a grain of salt. 
On the issue of your meds and depression/anxiety. Have you noticed the anxiety has gotten any worse since you’ve been on the Wellbutrin/Buspar combo? I only ask because that was one of the things they tried for me recently and it actually made me sooooo much worse. I know everyone is different so it could have nothing to do with that. And you have a lot going on so it could totally just be situational as too why yours feeling more anxious. But my doc did say there are some pts that Wellbutrin can make their anxiety worse. Idk, I would just mention it to your doc. If it’s something as simple as a med change that could bring you at least a little relief, that would be a start...a little bit of a help. 
You are stronger than you know. And no matter what you choose to do, you will get through it. Please be safe. And reach out anytime.