Game turn 2 fps for no resons since 2 weeks

I don’t know if it’s my pc or any thing else, but my game turn 2 fps some times like when i go back to the hangar or when i go in a game (mostly when i go back to the hangar) and i have a 50% chance for my fps to come back (after 30 to 60 seconds (approximative time )) and some times it’s in game and i have no option else restart my game or waiting until the end and prying the holy snale… at 2 fps…