I believe that this issue is likely caused by the transaction being dropped from the mempool of the Electrum server you are currently connected to, but still being available in others.
Your transaction was visible on a number of block explorers (but not all), which indicates that some nodes had dropped/purged it... and others had not.
If it happens again in the future, you can try:
1. Connecting to a different Electrum server to see if it can "find" your missing transaction
or
2. Shutdown Electrum, delete the blockchain_headers file from
the Electrum data directory and then restart Electrum
or
3. Try restoring your wallet from seed to force a recheck of all the data
For now... waiting is probably the best thing you can do... However, even with fees dropping quite a bit the last 24 hours, given the
current state of the network... I still don't fancy your chances with only a 9.5 sats/vbyte fee
You're most likely going to need to try and use RBF at some point.