Can the acceptance of a maid by word of mouth, followed by your feeling hot and having a headache, be an indication that you have contracted a disease, even though the maid's tests were excellent, and you still feel pessimistic?

One must repent from kissing a non-mahram woman, and be wary of anything that could lead to it in the future, such as being alone with her. The fever and headache are not necessarily due to the sin, but it is not impossible, for the Almighty's saying: "And whatever strikes you of disaster - it is because of what your hands have earned, and He pardons much" indicates that sins can be a cause of misfortunes. Fear of sin is a good thing, but one must beware of obsessive thoughts, for Allah's mercy is vast and there are many expiations for sins.