If this is how the lockdown is starting to feel for you, trust me, you are not alone. The frustration that many people are feeling right now may also be cutting into individual resolve where healthy, fitness and exercise is concerned, leading to a lack of energy and focus when exercising or considering doing so.
Though actually, the best way to deal with a drop in energy and the frustration that many are feeling at the moment is to exercise and to dial-up certain kinds of exercise (running, cycling, cross-training routines where possible), as these are not only energising in themselves, they also encourage a sense of communal effort and social solidarity. When you run, for example, you feel part of the world that is running around you (particularly if you do so in a park).
You are not a runner, you are one of the runners.
Ditto for cycling.
By exercising in a way that generates energy and which gives a sense of physical challenge and mental accomplishment, you also build a mental wall against defeatism and emotional drift.
Or, to put it another way, you fight back and put yourself in a stronger position to survive the current malaise and to be ready when the world rights itself.
The gyms, along with everything else, will (perhaps eventually) re-open.
Possibly not tomorrow, but it will happen.
Until then, stay focused and remain strong.