Performing all one's salaah for the day after work

Q: I experience constant doubts in salaat and I am currently combatting this. At the moment, due to work, I have to pray my isha, asr and maghrib when I get home in the evening. When I finish my prayers I doubt whether I have prayed asr for example and that I have maybe accidentally skipped this. I have no recollection that gives me complete certainty that I have prayed it or that I haven’t prayed it. But it can be said that because I have gotten to the end of praying all three prayers, it is likely that I did not miss it and this is just doubt being planted in my head. As I suffer from constant doubts is it permissible to ignore the doubt and deem asr to have been prayed, even if in reality (but unknown to me) my doubt is correct and I did not pray Asr?

Missing Fajr Salaah

Q: I woke up with my alarm fajr time then I saw that there was some time for Fajr salah to end. So I decided to sleep for some time or close my eyes for some time then wakeup and pray Fajr salah but when I closed my eyes I was getting too sleepy so I said to myself and also thought that if I close my eyes or sleep for some time Fajr time will be over but my intention was to pray salah on time. So later I woke up after the time was over...

I was so sad that I woke up after the time finished. This happened for the first time with me and it was never my intention to miss the salah. After waking up after the was time over, I prayed Fajr so is my Fajr valid?

I am so worried. I was sure that if I will sleep I will wake up after Fajr time but my intention was to wake up and pray in time and I slept to get up after some minutes but unfortunately I didn't wake up. I never wanted to miss the salah.

Nikaah without witnesses

Q: I did ijab o qbul without mehar and wali and without witness 8 years ago. There was no physical relation but I realized it is wrong. I left that boy now and my father is getting me married to my cousin. Should I get married to him or tell my father about the nikah 8 years ago?