I've looked around on the net, and found that some people are having to wait about an hour for their games to install...

However, my case is fairly worse.

Its been 5 hours and 34 minutes, but the instalation process is still at 33%

No, i did not leave PS4 at sleep mode, it has been all the time on, showing the S.P.E.C.I.A.L videos

(I must be such an expert at Vault-Tec's S.P.E.C.I.A.L now that i could probably qualify for overseer)

Any suggestions on what should i do?

You have no disk space delete some stuff, if you do have room delete what it did install and retry downloading it.

If its a physical copy take the disk out and clean it and try again.