Hi sonj,
Sorry to hear you are bad again. Loads of issues here.
Main question: why did you have further treatment from the Chiropractor if you were feeling so good? I do believe that he has helped you more than anyone else up to now, but you get to a point when natural recovery is best. There is a risk in manipulating a disc protrusion.
As I said previously, the majority of people with disc problems have flair ups of symptoms. Standard advise would be to give yourself a couple of weeks (don't panic the initial severe pain should start to settle), if you are not starting to improve after 2 weeks try and get another epidural as this did help you last time.
Disc protrusion into the end plate is relatively common and may have happened to you previously. This usually happens when the end plate is weaker than the annulus. It is often an incidental finding and can be seen when there is a previous history of Scheuermanns disease and are described as Schmorl's nodes. However, Scheuermanns usually does not effect lower lumbar spine. Schmorls nodes are often asymptomatic and I would not worry about this finding on youMRI.
Give yourself a few days for the intense pain to subside and then try and get up and mobile again. Please don't let this flair up cause you to get all that fear back, you are likely to recover and if you are not recovering then you still have the option of the epidural.