Swallow found unable to stand, it crawls and tries to fly

Im in Greece and found a swallow that crawls on its belly as it cant stand, and flaps its wings but cant fly.

Vet told me after giving it a jab its not with broken wings but an exhausted migration bird.

Its 5 days now im caring by hydrating with a syringe and making a bird meal pulp with water and gentle force feeding because it doesnt eat or drink what is put down.

I have been given bird rescue numbers in Greece but the mobiles are disconnected, voluntary rescue Samaritans.

Im wondering if maybe this bird has serious problem that it cant stand but crawls on its belly. Can it be exhausted that it cant stand up?

Its very trusting that i dont need to wrap my hand around its wings and sits or hangs on quite happy.

Feathers in good order.

Any suggestions?

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