Hello

Don't be feel sad, if you want to become a doctor then you should take a drop year which is your 4th one, Its never too late to achieve your goals and don't be afraid to give try and try because your experience of working and studying will be more than that students who just take a step, You are more than far from them. So, don't get demotivated it's your life, If you want to go grab it and with 101% hard work and consistency, I suggest you to use pomodoro method which is to maintain Focused in your way i.e 25 mins study and 5 mins break and then repeat this sessions 2-3 time and you can add more time like 1 hour study and then 30 mins break.

And if you want to become a doctor then there other courses in which you can go through check it out what if your marks matches with your course such as AYUSH( BAMS, B.U.M.S, BHMS) and you can go for B.sc in Biotechnology, B.sc in Radiology so many fields are there but i suggest you to take your decision wisely.

All the best for your bright future ahead!