lol dunno if I'm an expert! but I try.
Cypress, nice to see you like to lift! I actually did a style fairly similar to yours, where I would lift every day. (minus sundays for homework.) Doing upper then lower, then upper, etc. It works wonders for losing weight, getting fair definition and establishing good fundamentals for weight training, but I personally think it's a biiig no no, if you want bulk/strength.
And Freddy is correct to, usually after 3 days of doing (absolutely) nothing you might notice a small drop. You would regain it fairly fast and if you trained even harder, you would be fine! He is also verry correct on how you need proper rest, it's a fundamental element in proper training and health...
...I'm not sure on how your workout is set up through the week, or the intensity you take it to, but I personally don't agree that you should go a whole month then take a week off! Moderation is key.
If you can try for a 3-4 day work out program and see how it might work for you. You can do core lifts lets say, MWF and (if you want) do any cardio on TTH. Then use the weekend to relax and rest your muscles for the next week... That setup allowed me to gain 50 pounds in over a year of serious lifting, while giving you a fair amount of relaxing time.
I'm most worried about how you say your back has been aching! Thats really not good, no matter the cause of it! If there is any pressure or any awkward feeling in your back while doing any lift, stop and take time off like you where suggesting. (which is logical of course) Last week was my max out week of the month and tried doing 613 deadlift, from 603. I failed. I felt fine afterwards, but I ended up messing up a ligament on my right knee and now I'm taking off squat, powerclean, and deadlift for a little bit. The human body always breaks before the bars and plates to. : (
This is coming from a guy who takes this stuff to seriously, but I hope I can help somehow. Just find a good workout type for you, measure you progress and if it works... continue! Sorry for this mass of information, I dunno when to shut up sometimes with this junk. lol. (and I didn't even touch the topic of nutrition haha)