Please correct this para

[CONFUSIONSOLUTION]

Please make this para clearer with an advance level english.
In this case my exams are over just few days before and I am describing to someone how they were.
I really had a tough time doing these exams.On the firsy day of the exam I couln't complete 11marks question in the exam paper.On the second day my dad's bike tyre got punchured and I used to leave my home just half an hour before my exam as it just takes 15minutes to reach the venue on a bike from my place and I dint get a cab on time and I reached the venue just 5 minutes before the exam.On the last day the electricity was going and coming in between when we were writing the exam.I never had such a tough time in giving any exam than this

 

[emsr2d2]

Please make this para clearer with an advance level english.
In this case my exams are over just few days before and I am describing to someone how they were.
I really had a tough time doing these exams.On the firsy day of the exam I couln't complete 11marks question in the exam paper.On the second day my dad's bike tyre got punchured and I used to leave my home just half an hour before my exam as it just takes 15minutes to reach the venue on a bike from my place and I dint get a cab on time and I reached the venue just 5 minutes before the exam.On the last day the electricity was going and coming in between when we were writing the exam.I never had such a tough time in giving any exam than this

I had a really tough time with these exams. On the first day of my exams, I couldn't complete one question, which was worth 11 marks. On the second day, my dad's bike got a puncture and I had to leave home only half an hour before my exam was due to start. It takes 15 minutes to reach the exam venue on a bike from my place, it took me a long time to get a cab and I arrived only 5 minutes before the exam started. On the last day, the electricity supply kept coming and going while we were taking the exam. I've never had such a tough time with exams in my life!!

 

[CONFUSIONSOLUTION]

I had a really tough time with these exams. On the first day of my exams, I couldn't complete one question, which was worth 11 marks. On the second day, my dad's bike got a puncture and I had to leave home only half an hour before my exam was due to start. It takes 15 minutes to reach the exam venue on a bike from my place, it took me a long time to get a cab and I arrived only 5 minutes before the exam started. On the last day, the electricity supply kept coming and going while we were taking the exam. I've never had such a tough time with exams in my life!!

Hi,Thanks for your reply just want to check with you ,
1)"the electricity supply kept coming and going"I hope saying coming and going wont be wrong english right ,because we normally say on and off ,Can we make this better.
2)In the above case my exams are over a week before and I am describing the incident in the later week so I am suppose to say "THESE" or "THE" eg "tough time with these/the exams"
3) Also is that saying, " I had a tough time doing these exams " is wrong .Is the usage of doing correct in these sentence and when do use "doing" apart from when we want to indicate that we are doing some work.
5)"On the first day of my exams" On the first day I had only one exam so will it be "exam" or "exams" ,When do say "exams" and "exam" ,actually I am getting confused with the usage of "exam" and "exams" can u help me to understand when to say "exams" and "exam".
4) When do we say mark/marks eg "Worth 11 marks" in above sentence.Thanks ,Do reply.