Welcome Pat. Glad to head you are going to take your life back. Nobody can say for sure how long your withdrawals will last. You have not been using all that long so if you are in good health it shouldn't be too horrible. It sounds like you have prepared well and taking two weeks off work was a great idea and will give you the best chance of success.
For me the physical withdrawals while miserable were much easier to get through than the mental cravings and depression that came along with kicking opiates. Don't psych yourself out by saying it is the hardest thing you have ever done. It helps to have some confidence and say that you are sick and tired of it and ready to kick their A**! Yes it is going to be difficult, but if you go into it with a positive mindset knowing that this is part of the process and the worst will only last 5 days or so it is very doable. I kicked heroin several times and for me sleeping was my only true relief. Now sleeping can be difficult, but I always tried to just sleep through the worst of it (in between trips to the bathroom if I could even make it there).
Best of luck to you. Be mentally strong. Tell yourself you are NOT going to use no matter what. Getting more or taking a little just to take the edge off is NOT an option. You took this time off work for a reason. You might want to prepare for some type of help after the worst of the physical stuff is over. Whether it be a meeting or one on one counseling with an addictions specialist or an outpatient program. For me the depression that came after quitting was very real and it takes some time to get back into the swing of things. Remember this is normal, but see a doctor if you have any concerns. Hang in there buddy! Keep us posted on your progress.