This is because your ukulele is tuned to sound exactly like a guitar. There are some people who prefer this type of sound mainly because the ukulele is easier to play. This is ideal if there are some songs that you have always wanted to play in your guitar but can’t because the chords are a bit harder to play.
A tenor ukulele can produce the most guitar-like sound. If in case you would like to have a ukulele that truly sounds like a ukulele, a concert ukulele will be fine. A soprano ukulele will also have a higher tune than usual. It might produce the ukulele-like sound that you have always wanted.