Have your back to the wall
Definition 1 of 2
Pro Tip 1/3Desperation Implied
Indicates a sense of desperate situations, often with a feeling of last resort or no escape. 
With creditors closing in, she had her back to the wall and had to sell her house.
Pro Tip 2/3Urgency
Suggests that there's an urgent need to act due to the limited options available. 
As time ran out, the team had their backs to the wall and played more aggressively.
Pro Tip 3/3Emotionally Charged
Conveys strong emotional distress or a high-stress situation that one is experiencing. 
After losing his job, he had his back to the wall, scrambling to support his family.