I think much better to give the bitcoin address and the the transaction ID of what transaction you mean that your bitcoin was missing..
We will try to investigate what the issue or cause of the wallet you are using.. Honestly i am not using 3.0.2 except for electrum 3.0 in mobile i didn't experience any problem the same as yours.  And like the other said my guess you download a fake wallet software which is possible there are somebody trying to steal your bitcoin from your wallet.

My suggestion right now if you are not using the segwit wallet better to use the low version of electrum wallet like what i used right now try the electrum 2.9.2 this wallet for me is stable or the recent version 2.9.3 you can download here http://download.electrum.org/
Please use my link not use the other link or searching from google because maybe you can get a fake link.

How long you use Electrum 3.0.2,are you maybe make update of old version recently and maybe download fake wallet?Only site for download Electrum wallet is https://electrum.org/#home and if you download from any other site you will get fake version which steal your BTC.

Do you have copy of your seed/private keys on your PC or did you share it with anyone?

If it is none of the above then you get infected by keylogger or RAT virus,it get remote access to your PC and wait to you enter password in your Electrum-then it was easy for hacker to send all coins to his address.

Is your balance now 0 or you see something?If it is 0 then I doubt that anyone can help you...

what balance are you seeing in the bottom left corner of your electrum window? if the coins are in your wallet they would be reflected in your balance.

if the money has left your wallet then there is nothing you can do about it.

yellow means it's a change address in your wallet. anyway looks like your funds were stolen. sorry for your loss.