Your ex simply isn't capable of shouldering your emotional burden as well as her own. She wasn't prepared for it and she was honest about that with you.

this is going to get harder the longer it goes on for both of you. Go back to your apartment with your roommate or by yourself, or find another friend or family member to come get you. Utilize the other external support options you have available to you. Call your support network or professional or hotlines. You're not the only one suffering like this right now, there are places making plans to help people just like you. Find them.

Your ex isn't a trained therapist, she's not equipped to help you right now. You're putting yourself and her at risk. Ultimately you will not be able to rely on her for the duration of this isolation, which despite certain leadership opinions will probably extend for at least a few more months. You need to get to a place where you can be stable on your own or with people who are willing and able to support you.