I just wanted to share something that my Naturopath told me regarding probiotics, which may apply to you by the sounds of it. If you're gut flora is comletely out of wack you're wasting your money on buying probiotics - because the environment in your gut doesn't support them and kills them off within an hour of ingesting them. My Naturopath told me to start from scratch and build up a 'probiotic friendly' environment to which she suggested taking colostrum. Once your gut is re-established you can go ahead with probiotics when your body is capable of actually absorbing them.
Also for constipation - an 'overdose' of vitamin C works as a laxative without causing dependence. If you take it in powder form make sure it is a gentle formula (I use Eagle's Beta AC powder - not sure if that's available in the states)
Also, 'Lower bowl stimulant' is also a good herbal laxative...
Anyway, not sure if this was helpful at all... Good luck to you :)