Anxiety came back. What to do?

So to my knowledge, my first anxiety experience was with an edible in november.  I fell into my first anxiety cycle last december, when I found a lump on my chest and thought I was going to die.  For a month, I had constant doctor visits for an ultrasound and blood work and I convinced myself I was fine.  I came back to college in January and ultimately forgot my anxiety for 3 months.  Now, this past week I seemed to relearn my anxiety.  Now, I fear death in general and just last night I was scared to sleep and I do not know why.  I randmly had one thought saying "what i you cant sleep?" After that, I was up for two hours panicing, until I used the calm application and controlled my breathing on my bed.  I eventually fell asleep for an hour, then back again for four hours.  My anxiety was gone for 3 months then came back.  What do I do to get over it again?

Edit: My anxiety isnt as bad as before, as before it was so crippling I had to stay in bed. I can function properly now, as I only get thoughts, but I forget them as the day does on.  But, at night it seems harder

I think that you need to build your own bank of things that you can use that work for you. CBT can help in trying out different techniques to manage thoughts and control anxiety. I think if you have a few things to fall back on if one doesn't work on a particular day you can try another. Breathing techniques, journaling and writing down anxious thoughts and challenging them and yoga have helped me in the past.

Has anyone else experienced this? My anxiety back then was health related, and was constant.  Now, my anxiety came because someone my age passed away and it really affected me.  If anyone has any tips on how they overcame another wave of anxiety lmk!