We can understand what you must be going through.
But just one step down does not mean that you have failed. You will surely be able to compensate for the loss.
About your query, yes you can certainly clear the back-log and consider taking coaching in the architecture entrance exams.
You can appear for NATA or AIEEE and clear them and pursue your architecture which is a course 5 years.
For more information on the career,its scope,requirements,benefits,remuneration,opportunities etc log on to
This should help for now.