I have tried drinking plenty of water but it still is not working for me. I am trying to sing more smoothly than i normally do, mostly my voice comes out as though am struggling to sing which should not be case even though it is true.
If you are struggling to reach, then it will be apparent to everyone, including you.
Practise may improve things, but you might simply be in the wrong key for your voice.
Sometimes you will find songs you can hit all the notes of, but some of the 'big notes' [the money notes] are right where your voice would really prefer to switch to another mode. You can try to practice your way out of this & over time your 'switch point' may change - but unless or until it does... pick another key.
Some people, though, sound like they're in the wrong key even if they're actually physically comfortable with it.
Case in point...
It's apparent to me right from the start, but the bridge & chorus from about 1 minute I think really shows this up.
[I'm afraid this is going to be another one of my 'anecdotal evidence' answers ;-)
I know for certain that he is perfectly capable of reaching this... because it was once playing over the 'muzak' in a hotel bar & I made the mistake of commenting about my thoughts on his strained vocals to my friends I was there with at the time - then sudden realisation hit me. They produced the damn record & I'd completely forgotten.
I completely failed to hide my embarrassment, but we did have a long & productive conversation about it.
Each of us is designed slightly differently, in many, many ways, one of which is the basic range of our voice. That's why some singers sing a particular song in one key, others in different keys.
You have what you have, and maybe it can be stretched a little higher, maybe not. If not, then you have to accept the fact, and sing in a range that suits your voice. Most of us have a 'head' voice, which may be what you mean. It's often not as strong as our chest voice, and the quality is different, sometimes even not as good as our chest voice.
Whatever you do, you're ony going to gain a couple of tones higher, so accept what you are, and enjoy what you have. I'd like to be taller - fat chance - so I put up with it. What else? High heels..?