Don't feel that low that it leads you to fatal and nasty situation. Be positive and start again with a fresh mind and with no second thoughts. You have realized the mistakes take the notes from them and try not to repeat them. These will lead you a much better possibility of not running any mistake.

You can follow the books mentioned below for your bank exam preparations:

Quantitative Aptitude - Objective Arithmetic by Rajesh Verma.

2. Reasoning & Logical Ability - RS Aggarwal or Pearson Guide.

3. General Awareness & Current Affairs - Competition Success Review Magazine

4. Computer Knowledge - R Pillai (Arihant Publishing)

5. English (Grammar) - SP Bakshi.

6. English (Vocabulary & Usage) - Word Power Made Easy by Norman Lewis.

Do a lot of practice and go thoroughly. Give the mock tests now available online and you can do it very good.

You can visit the link below to know more about IBPS PO or Clerk exam:

https://competition.careers360.com/articles/best-books-for-ibps-po

https://competition.careers360.com/articles/best-books-prepare-for-ibps-clerk

For SBI PO you can visit the link below:

https://competition.careers360.com/articles/sbi-po-preparation-books

For SBI clerk you can visit the link below:

https://learn.careers360.com/jobs/sbi-clerk-preparation-material/

I hope my answer helps. All the very best for your future endeavors!