There will be a game update on Tuesday (Tomorrow) you should find something new to do. It is not the end of the game. As you say you can still finish some of the contracts, upgrade both your buildings and ships, plus mine resources. You will need all in due course. There are many players including myself ( lvl 422) who are at higher levels. It gets more difficult to achieve completion the higher you get as the tasks are balanced by your level. Believe me you will need more efficient buildings and ships the higher you get.
