Welcome to the forum, Deetree~
Since the U.S. doesn't sell Mersyndol, it's possible that some forum members haven't replied because they don't know what it is. I had to look it up myself and found out it is a combination of codeine, acetaminophen (Tylenol or paracetamol) and doxylamine (an antihistamine).
Usually withdrawals are different for each of us based upon our age, how long we used the drug, and the strength of the drug. If you took you last pill on Sunday night and it's Thursday where you live, you would be right in the thick of it girl!! The first week is physically the hardest and particularly around days 3 and 4. We GRADUALLY make progress from there.
Since you used for 7 years, it will take some time for your brain and your nervous system to heal. But there are some basic things you can do to get you thru: stay HYDRATED, get some mild exercise even if it's just walking around your house, take Pepto or Imodium for tummy/bowel issues, eat comfort foods or drink a protein drink of some sort (amino acids are important as well), get some electrolytes by drinking a sports drink or even better a packet of Emergen-C, and take some HOT Epsom salt baths. For sleep, you can drink some hot teas like Sleepytime or Nighty Night or you can use some nervine botanicals to help you relax. They are plant based herbs that help relax our nervous systems. Some examples: lemon balm, passion flower, chamomile, valerian, etc. Watching funny or uplifting shows/videos and listening to MUSIC will both help as time seems to drag on.
I have probably forgotten some things, but feel free to ask and someone will help with whatever symptom is bothering you or with any questions you may have. The first week is the hardest and you are half way there! Good on ya for making this decision!! Wishing you the best~