Maybe all the cleansing is really hard on your body and is just dehydrating you. Then you went walking for 7 miles. Did you drink a lot of water when you went walking? Not having enough water after a super long walk could really make you feel exhausted and cause pain, especially if your organs are already suffering from so much cleansing.
Also, are you taking probiotics? I have not done as many flushes as you, but in my experience, my body feels a lot better after I get back on my Threelac after a flush. It energizes me. I've taken many probiotics out there and it's my opinion that Threelac is awesome in comparison to the others. I feel refreshed after sleeping even if I only sleep a few hours and I have dreams, which I didn't before. I feel active and happier and all-around better. You may have another probiotic that you prefer more. Start taking it as soon as it's safe to eat after a flush if you aren't already doing so. It will replenish all the good bacteria after your flushes.
I would not do another flush right away if you're feeling this weak after the one you just did. I do hope this helps. :)