1) The first question is about wudhu. As I woman, it’s happens that when I am washing my feet some air enters the front passage as the washbasin is fixed high, and when I start praying during prostration I feel some residue of that air in the woman front passage? (It’s happens even more frequently few days before menstruation) what should I do? Break my salah every time?

2) the second question is about signs of purity after menstruation. It is very difficult for me to determine when I should do ghusul as I do not find the white thread like. So after many many researches I found that total dryness while wiping(no colourish discharges) after answering the call of nature can be considered a sign of purity. Is it true?
As a full time university student how can I determine when I’m pure and which prayers I have to make up as I am in class all the time…

3) when it’s not possible to do istinja, I do istijmar (wipe 3, 5, 7 with toilet paper), in this case should when it’s time for salah should I change my undergarments?

4) waswas make me so anxious during salah, wudu and ghusl. I doubt so much and ask my self how many rakahs I did or if I forgot to wash a member. What should I do?

5) very often I forget if I did my istinja and keep changing my underwear what should I do?

6) after taking wudu can we recite shahada by heart in the bathroom?

by

1) ignore all doubts and continue as normal
2) if you have a period of habit (like 5 days) then you can use those days to determine when to do Ghusl
3) if any najasat is on undergarments then you need to change if not then no

4) try to ignore all doubts for rakats you can use a counter etc

5) totally ignore