Given that you are already suffering from premature ejaculation. It becomes important to restrain and control indulgence. That's a way to improve the quality of the sperm.
Next Steps
you need to meet a doctor to help you out with medications and other needs
Health Tips
1. Have strengthening foods like Milk, Fruits etc to manage situation from worsening
2. Be sincere in abstaining from sex especially this summer, Helps to improve a lot of things.
3. Timely Food and Some exercises needed on a day to day basis.