I need tips from anyone who had it get really bad again after a period of recovery 🥲 How do I break this loop?

(Before anyone tells me this yes I'm planning on going back to therapy after 4 years of not going in January, I unfortunately couldn't afford it until now)

I'm 23 and have had this phobia for as long as I remember, and when I was in high-school it caused me to develop severe agoraphobia and an eating disorder for about two years. It eventually got better especially for the fear of getting sick myself part. I guess the fear of seeing other people get sick was a bit harder to her rid of, and it's getting really really bad again now.

Basically a few months ago my sister got really sick and it triggered something in me that made the phobia spike again, I guess because my house is really small and we only have one bathroom and that's literally my nightmare scenario. Ever since then, I found myself being scared of it happening again on the daily and checking for signs and having nightmares about it all the time. It has somehow happened twice again throughout the past months and it felt worse every time. Now I get panic attacks about it every evening and I keep repeatedly checking for signs of it happening (the last two times happened because of a migraine so I keep asking her if she has a headache) and I'm hypervigilant about her behaviour 24/7 like checking if she looks more tired than usual less hungry etc. and my ocd compulsions related to it are getting really bad again😭😭 I'm so frustrated with myself because I thought I wouldn't feel like this anymore after all these years but here I am......

Has anyone experienced anything similar? 🥲🥲🥲 I feel like all the tricks I used to use to calm my anxiety aren't working anymore....