We can't really be a 100% sure. As your HDD is making clicking sounds, there's a probability that it is failing. This is why, it is good to back up the most important data stored on it. In case it completely fails, you will not be able to do so.
You haven't mentioned about the PSU problem. This could have damaged the HDD or may not supply power adequately to your HDD.
Anyway, you need to do some troubleshooting in order to narrow down the possible causes.
- Attach the HDD with different cables to a different port. In case you can attach it to another system, you will be sure whether there is something wrong with the HDD or with something else in your PC(most probably PSU).
- There are some software tools which you can use to test your PSU. Though, the best thing you can do is to just borrow one from somebody and install it on your system.
D_Know_WD