I know I need to get a grip and there's always people worse off
This is a pretty harsh and unhelpful way to talk to yourself. It's about what you're dealing with, not making comparisons. Try to be kind and compassionate towards yourself.
It's a frightening and uncertain time, so your feelings are natural. But there are ways to manage them, distract and soothe yourself.
Try to keep bringing yourself back to the present moment only rather than your fears and worries of what might happen. Focus on just what's going on now, how your feet feel beneath you, the sounds around you, your own breathing.
There is an app called Breathe that some people find helpful to calm their breathing.
Even if you have a full blown panic attack remember your body can only sustain such an intense state for a limited period of time so it will end, and when it does end you can rest and soothe yourself, focus on coming back to the present and then see if you can find distractions.
What do you do to comfort yourself when you're feeling tearful? I have a blanket I wrap myself in that helps a bit.
What distractions do you have? They can be as big or small as your concentration allows. I'm using a colour by numbers app a lot at the moment as I find it soothing and distracting when I feel overwhelmed.