Your tx will either get confirmed at some point or rejected by the network and will return to the wallet it was originally sent from (and which most probably used less tx fees than it should and this is why your tx is stuck now).

Regarding your 2nd question: https://coinomi.freshdesk.com/support/solutions/articles/29000009720-what-will-happen-if-you-stop-developing-coinomi-or-shut-down-every-server-will-i-be-able-to-recover-