Relationship issue : I am having trouble getting determined, thus getting anxious

So it's about my current relationship going through hard time. Me and my girlfriend are in a really long distance relationship. She is under immense pressure of her studies preparing for exams next year. She told me it's difficult for her to 'maintain' a relationship because of the current situation and she is finding herself to be irritated at people and even me at times and the thoughts of killing the relationship often pops up ( She has this tendency to cut off people impulsively whenever she's going through hard times) and also having thoughts of smoking and drinking to ease the pressure - which is very unusual for her.

I understand the the situation she's in and I asked her to focus on her studies and not worry about me. But at the same time I am getting anxious about her mental health as well as my position in her life. I know I sound selfish but I tried my best to leave her be. Thing is, even if we decide to stop communicating, we can't - we have tried this multiple times over multiple months. So while being worried about the relationship - as I am scared of losing someone I love thinking about the effort I put in a relatioship, I am worried about her as well.

I have developed anxiety and I can't seem to get through the day. I wake up, thinking of texting her even though we talk randomly everyday - I think this is because I want to be ensured that i still have her, I have no appetite - most of the time I stop the urge of puking while eating, my eyes feel drained and I feel completely demotivated. I decided today that I will be strict on myself and make sure I am healthy and happy and not think or worry about the relationship. Also I am afraid that this just might fail because I am unstable and not thinking straight.

Thank you for reading. I don't have anyone to share it all with and I would really be very thankful if anyone can support me in anyway, even a few kind words are appreciated, it will just make me feel strong. :)