Started Sweatfest 2nd time. Hurt back but don't want to skip workouts



I started in on getting back on track after the holidays and was already (despite my brief hiatus for about a month and lots of feasting) starting off in a pretty good place. I started Sweatfest again because I felt like I had pretty good results from it back in Sept/Oct. Was heading into my second week of it, Day 9 to be exact, and my back started hurting really bad on Monday night. I was forced into not working on Tuesday on account of the back pain, as i work a physical job. I could barely get into and out of bed without sharp twinges let alone work on my feet all day moving around, lifting twisting and turning with large heavy boxes all day.

I did, however, go for a very long brisk walk on Tues. About 4 miles. Wed I did 30 mins on the elliptical followed by an upper body strength video and a half-hour arm toning workout. Both independent of and in lieu of the scheduled FB workouts on my calendar. Yesterday was my birthday, so there was much relaxation and indulgence. Today I went back to work although I was not very physical, mostly standing or slow walking around while working, and I left at 2 so....

Here I am. I have missed...3 days' workouts on my calendar, 4 if I skip tonight's. I know they say if you miss too many days to start over, but what if you supplement they have for you with other workouts?

Going through FB Sweatfest for another round I am finding myself frustrated that so far it's all been HIIT workouts with some stregnth. I feel like my legs are neglected.

Anyway, annoyed to see what is scheduled for tonight and see yet again nothing but more burpees, fast moving up and down motions, etc. I just can afford to make fast sudden motions right now and especially cannot be putting any strain on my back bending over, working my abs, etc.

What should I do? I hate starting and not finishing because I would like to be consistent with my workouts. Do you think if I continue substituting what is on my calendar until I am better/feel recovered enough to resume their daily stuff, it is just as good and can pick up where I left off? Have come too far to start derailing,

Meow :(