Jokingly getting married

Q: Does a nikah done as a joke (just for the sake of fun) in a friends gathering without the presence of the wali, become valid?

Is it valid when the girl says yes just because of peer pressure of acceptance in a group and without having the knowledge of the sensitivity of this subject/issue of nikah.

Boy studying with girls

Q: I am a boy who studies in school. I am very shy and modest and I do not like to be mixed up with girls. In my class I am from the engineering group in which there are 3 girls and 2 boys including me. My friend is mostly absent, so I am the only boy studying with the other 3 girls. I am very tense because of this as this is against my nature and I cannot tolerate this.

Moreover, those 3 girls like me and irritate me intentionally by continuously looking at me, or speaking only when I ask questions from teacher and intentionally going into and out of the classroom near my desk. I am very worried and cannot even study properly because of this as thoughts about those girls constantly come to my mind. What should I do to get rid of these girls.

Reciting an amal during haidh

Q: A few weeks back my father met a Moulana, who gave him an amal to perform for solution to any problems.

Starting on a Thursday night either after Maghrib or Esha salaah, without communicating with anyone, one should recite the following 11 Durood before and after 70 X Surah Fatiha on Thursday and should be decreased by 10 each day thereafter. The amal should be repeated for 5 weeks without any breaks.

I would like to that during the period that a female experiences her menses, does she stop performing the amal during the time and restart on the first Thursday after she becomes paak or can she continue performing the amal.