Fomo app balance fell to zero after a memecoin purchase

I bought a memecoin for around $100 through the Fomo app. It initially showed an increase of roughly 18%, but when I checked again the position displayed a zero-dollar balance while still showing me as a holder and still showing the gain percentage.

The coin itself was still moving and did not appear to have simply failed. Fomo support told me that I had been hacked and asked whether I had clicked a link. I do not know of any link I clicked, so I am trying to understand what could have happened.

My bigger concern is that I use the same email address for another crypto account. I have used Fomo for memecoin trading for more than a year without this problem, so the sudden change has left me worried about what access may have been compromised.

I am looking for practical guidance on securing the affected account and checking whether my other crypto holdings could be exposed.