Ref. No. 41/968
In the name of Allah the most Gracious the most Merciful
The answer to your question is as follows:
In the above mentioned case, only Wudu will suffice you. Ghusl becomes obligatory only when one is certain that it is wet-dream. You can make wudu and perform namaz and avoid waswasa. Additionally you had better consult a doctor for treatment at earliest to get rid of the waswasa.
And Allah knows best
Darul Ifta
Darul Uloom Waqf Deoband