Dear human, thank you for sharing and reaching out. You have taken the first step in your mental health journey and I appreciate you for reaching out, it takes courage. I can imagine that it must not have been easy for you to do this. I understand that what you're going through can be tough, and this journey must've been challenging.
I highly recommend that you approach a psychologist and seek professional help for your concerns. Therapy will help you cope with your stress and fear and uncover the underlying reasons and thoughts behind these symptoms.
Fast heartbeat, headache, and nausea are all physical manifestations of your stress and anxiety. It is the body's reaction to what you're going through psychologically.
You can try the following relaxation techniques to cope with this till the time you get professional help:
1. 5-4-3-2-1 exercise - Whenever you feel like you're getting into the spiral of overthinking or you feel stressed out, take few slow and deep breaths and name five things in your environment that you can see, four things that you can hear, three things that you can touch, two things that you can smell and one thing you can taste.
2. Remind yourself to breathe deeply and slowly, notice and focus on your breathing for a few minutes.
4-7-8 breathing - inhale for 4 seconds, hold your breath for 7 seconds and exhale for 8 seconds.
Take breaks and be patient with yourself; it's not easy what you're going through, and showing yourself empathy and giving yourself time will help.
Definitely seek professional help to deal with this in the most effective manner. Prioritize yourself and manage your concerns more actively with the guidance of a therapist.
Next Steps
Hope this helps :) Take care!