Thanks for Replying Kentuckienne!
And thankyou for that useful information. I will be sure to try out this recipe in the future. Hopefully he Enjoys it!

UPDATE
Hi everyone!
As of yet, I haven't been able to get little Ollie to a vet but arrangements will be made soon. There have been some changes in his behaviour and I would like to share them with you.

As I mentioned before, I have noticed that Ollie has been making a baby screech when people are around him, and he would screech louder as you approached him. However, I have realised that he is not hungry or wanting attention. This has been constant, and he has become increasingly afraid of humans. Just recently, I tried to take him out of his cage, but he refused to approach my hand. In fact he jumped off one of his perching sticks to avoid my hand. I became worried that he has developed a serious distrust in humans.

Today I tried something different.
I was mixing up his nectar food for lunch and thought that I would try to hand feed him, to build that trust. He refused to come near my hand, but was very very interested in the food in the bowl. I decided I would leave the door open to his cage, and place the bowl outside of it, to encourage him to come to me. I sat just behind the bowl. He had no trouble approaching the bowl to eat, but when i put my finger out (between him and the bowl so he had to stand on my finger to eat) he would run back into the cage. I tried this for a really long time and he started to pretend that he was giving up (pacing back and forth in the cage waiting for me to leave so he could eat.

Eventually, i tried holding the bowl in my hand, and moving it towards him. He jumped straight onto my hand and started to eat. I saw that he was wide eyed and looked uneasy. I let him eat for a while and then i started stroking him while he was eating. He didn't like it at first, but soon enough he was happy to sit on my hand. After a while, my arm got tired and I thought that it was enough and I decided to put him back into the cage. I reached inside and placed down the bowl and tried to get him to go back into the cage to eat, but he refused. Instead, he ran up my arm and perched on it. I gave him a head scratch and he loved it. He was happy to sit with me. So i decided I would take him outside to play in the grass. We had a good play time and we hand wrestled for a while. He started to dive into long grass and bury his head in it. I could tell he was really happy to be with me. He didn't want to leave the grass in the end, but when he saw me leaving, he stopped playing and climbed up into my hand. He has stopped making that noise since. But I am yet to say that this is the end of his behaviour problems.

Still, I am so excited to see how close friends we can be!

that's really good to hear but please never take him outside without a harness again. There is nothing to stop him flying away and getting hurt.

What you may have found at first is where he was hurt and in shock he was compliant with stuff but now he's feeling better and has settled his instinctual fear has kicked in

Thanks LordTriggs
That's a really good idea. Since you mentioned it, I had never heard of a bird harness. I can see the danger now. As of yet, I don't need to worry about him flying, he is still too young, but it is a potential hazard of the future. I will make sure i'm more careful with that.

Yes, what you are saying makes sense. It explains why he was so complaint at first. I am glad to see that he still likes head scratches.
Thanks for your help man!