I suggest you start a journal. List the concerns/stressors you have.
Break them down between the concerns/stressors that you can impact and those that you can't.

For those that you can not impact, decide on a thought to divert your concern.

For example,

Grandma, The doctors are doing all that they can to help her.

Your heart palpitations, Again, the doctors are aware of your condition and are doing all that they can. Plus, anxiety will only make it worse.

List what you can do to impact those concerns. Make a plan to do those things to impact those concerns.

Grandam; She knows I love and care about her but I will keep telling her when I have a chance.

Your heart; I've taken my meds. I'm eating healthy.

Your class, My homework and studying is done, or I have set time to do my homework and studying for ~ 6:00 to 8:00 ~ are whatever.

Think of the Serenity Prayer :
God, grant me the serenity to accept the things I cannot change,
Courage to change the things I can,
And wisdom to know the difference.

If you have noticed by your young age, most seniors do not get upset or worried about many of the things that upset or worry young people. They have many years of experience and know that very little of the things that people worry about can be changed, especially by their worrying.

Your generation often gets stuck worrying about what others think. There is an adage that goes: If you only knew how little time others spend thinking about you, you would stop worrying about what they think may about you.

Make notes to remind yourself of tasks you need to do. When you right the task down, you can let go of it in your mind.

Now, decide to do the completable tasks and let go of those tasks that you cannot complete or impact.

These are skills that will benefit you for the rest of your life. Most people take decades to learn to let go of worthless worries and anxieties.

Understanding your symptoms is a good way to accept them and work with them. The frustration of fighting against your symptoms is a self-defeating task.

Some of your stressors need to be individually analyzed.
For example; Your ex-BF.
Why do I need a BF?
or... Do I need a BF?
What benefits do I get from having a BF?
What liabilities to I take on when I have a BF?
Does a BF get in the way of other issues in my life right now?
Am I less of a person without a BF?

Your family's financial issues
What am I doing to help my family financially?
What am I doing that causes difficulties for my family's finances?
Can I make an impact on my family's financial situation?
If I try to make a positive impact on my family's financial situation, do I risk making things worse?

Most financial issues are best handled without emotional involvement. Emotional decisions are the leading cause of financial difficulties.

Get the idea?

You have a great opportunity to start thinking about your life in meaningful ways.