Hebrews is tough going. I chose it because I thought it would be a change from John (which it is!) and because I don´t know it as well as other parts of the NT. I guess part of what makes it difficult is that the intended audience obviously has a very different background than me, making it not as easy to relate to as other books, but this is also partly what makes it interesting - seeing how the story of Christ was presented to the Jewish people and how the NT and the new covenant makes sense in light of the old. But it´s also taking me a long time because I now have so much reviewing to do that I have slowed my pace to only 1 new verse a day, giving me time to go back and practise other verses, and this makes a huge difference to how quickly I get through a chapter! But I´m more than halfway now, so we´re getting there :-)
Hmmm. Ok. That's not what I wanted to hear. I had planned to do Hebrews after John and I still want to but I'm still recovering form 1 John :S I don't know why but it was really hard, not to understand, but to memorise. I listen to it 5 times a week and I still don't have it down! It does seem different to everything else though. I might fit in Philippians before tackling it just for something small.
Not sure what you´ve learned so far, but Colossians, Ephesians, Philippians, James, Galatians and 1 Peter are all fairly short and full off good stuff. You also might want to consider learning Hebrews 11 and then just reading through the rest of Hebrews without learning it all fully.