Hi - I am a colonic hydrotherapist and have patients presenting these symptoms all the time.
Obviously I don't know your patient history but normally........
Patients with these problems tend to drink less than 2 litres of water a day, drink tea, coffee and fizzy drinks instead and often suffer with bloating, bad breath (sorry!) and difficulty with going to the loo - which is what you have suffered from for a long time.
If this is you then the chances are that you are very dehydrated (many people that are really dehydrated dont feel thirsty as their bodies have given up any hope of ever being heard!) which is one of the reasons it's difficult to go to the loo.
You've recently lost weight (well done!) and a change of diet can affect the bowels. Often the bacterial balance in the bowel can be affected and make it more difficult, and if you were a fizzy drink, tea and coffee drinker then the chances were that the bacterial balance was off anyway.
If any of this is true then I suggest 1 thing to start - drink more water!! It will make your poo softer so it's easier to pass, it will help with weight loss as water flushes the system and the body releases toxins. It will also help with the rebalancing of bacteria in the bowel - if you have Candida (thrush of the bowel - and I suspect you do) then more water will make the bowel moister and less habitable for the candida.
Candida is sortable - you need some of it in the body to keep the poo soft so it can come out easily! Too much and you will either find it too easy to go or too difficult depending on how your body works!
Laxatives make the bowel lazy and will make it more and more difficult for you to go to the loo. As the muscles around the bowel (peristalsis) don't have to do anything because the laxatives are doing it for you they gradually slow down until they dont really do much unless they really have to!!
To wake up the peristalsis water will (of course help) as will eating foods that will give the muscles something to do. Think about what you are eating - anything that you can crush in your hand may be good for you (salad etc) but doesn't put any bulk in the bowel and therefore doesn't give the muscles anything to push against. Try eating organic brown rice a few days a week, and linseeds soaked in water every day. These are more natural ways of helping the bowel and they do work
You should of course take this information generally and take advice from a professional who knows you before taking any action.
If this doesn't relate to you get in touch and I'll try and help more!!
Don't worry - I see a lot of this and at not once has it been serious!
Take care - let me know how you get on!
Tracey