I need recommendations for books

[GoldenEyedScout]

The Discworld series does a wonderful job of mocking every fantasy cliche and trope, and you can read the books in any order. My personal favorites are Unseen Academicals, Going Postal, and Mort.
On the sci-fi front, Dan Abnett's Embedded is absolutely incredible. He's always done well with his 40k books, but because he's not constrained by the universe with this one, it rises head and shoulders above.
If you want memoir/autobiography, Black Coffee Blues by Henry Rollins is one of my favorite books. It's part memoir, but mostly poetry and short stories he wrote while on tour with Black Flag. Either of Chris Jericho's books (A Lion's Tale: Around the World in Spandex and Undisputed: How to Become The World Champion) are funny and enlightening.
Hope you feel better, and I hope these help.

 

[Ed130 The Vanguard]

Not to go on like a broken record but Terry Prachett's Discworld novels have hope and humour in abundance. The Edge Chronicles are a little darker in tone but are also worth reading.

 

[NoPants2win]

Ivanhoe by Walter Scott is a good read. It's like a more friendly, up beat version of Game of Thrones. It's been out for a while too, so if you don't want to buy a new copy your local library probably has one.

JPOD by Douglas Coupland is a pretty fun read.

Also, Fool by Christopher Moore is crippingling hilarious and would probably brighten your spirits.

 

[COMaestro]

I will skip few obvious ones and go straight for rarely heard ones
"Myth Adventures" series by Robert Asprin
(comedy+fantasy+sci-fi+anything else author wanted to put in)

When I went home last night I saw these books on my shelf and thought, "Why did I not recommend these!?" The Myth series is hysterical and well worth reading. Starts with "Another Fine Myth". The Phule series by Asprin is good as well, if you want a futuristic sci-fi military comedy. "Phule's Company" is the first in that series.

There are so many good books out there, it is impossible to get through all the things I would suggest. As others have stated, "Ender's Game" is definitely worth a read, though I think the sequel "Speaker for the Dead" is the best book of the series.

The "Death Gate Cycle" was also mentioned and is a very good seven book series.

I have only read the first book of the "Percy Jackson" series, and though I did enjoy it, it felt so much like it cloned Harry Potter, right down to the three lead characters. However, it does suggest that you would probably enjoy them if you like HP. Someday I'll read more of them.

So many more that could be mentioned, but I think you've got enough suggestions on your plate

 

[Flight]

I recommend Meredith Ann Pierce's The Darkangel Trilogy, if you can manage to get ahold of it. I found it quite lovely, and the mythology interesting. The Sandman series, by Neil Gaiman, is also very good. They're comics, though. I hope you feel better soon!

 

[Shocksplicer]

I recommend the "Tales of the Ketty Jay" series by Chris Wooding, starting with Retribution Falls.

It's basically a retro-future version of Firefly.