Nice to see you're giving it another go - without knowing what you were eating its very difficult to advise much so my best advice would be keep a note of what you're eating ie start a journal - then you can try to identify what is causing the problem.
I personally stopped dairy for a while, others have stopped nightshades so the key will be there you just need to find it.
I'd stick to plainish food for a start ie Roast meat with roast carrots, onions, mushrooms for tea - cold leftover meat salad for lunch, chicken, prawns or berries for snacks, that way it'll be easier for your stomach to get used to the idea rather than throw lots of spices and things at it that it may not be used to. I found that toilet wise it can take a couple of weeks max to get used to the fact that you will do far less so don't expect things to be the same as you are putting less rubbish in so you'll get less out. Theres no need to strain or take supplements to cause movement. Also I would just eat whenever you are hungry which I think is more than people generally eat when you start - what will an extra couple of days of weight loss matter if you are feeling better to start and actually make it work.
Plus - take a couple of days off or plan it over a weekend so you'll feel more able to take the time and experiment to sort it out if it does occur again.
Hope this helps