Thanks for your query.Based on the facts that you have posted it appears that consistency of your semen i watery in recent times.
Thickness of the semen is variable from person to person and even in person at different times.The commonest causes of the watery Semen are
1)Quantity of sperm cells may be less.due to repeated ejaculation or due to age factor. (Less production of sperms by Testicles)
2 Less production of fructose by Seminal Vesicle
or excessive consumption of body glucose
in other activities like exercise and work.which is possible in your case.
This is not due to infection
Please take high protein diet rich in fruits and sugar.
Do not worry it is not a serious issue that you should be scared about.