It is often the case (especially in India) that first-time managers don’t get any training on how to manage others. Especially if your organization does not have set processes or structures, it might be hard to match expectations in practicality. This could be because of the overestimation of output or because you are underperforming.
Check if you can find time with another colleague (with more years of experience) within the organization who can help clarify your goals and provide some perspective on realistic expectations. Seek feedback on how you can improve your performance.
If you feel comfortable, speak to your manager, and clarify expectations and negotiate more reasonable goals. You can suggest more resources to be added to the project or put in extra time.