Hi Laura,
Firstly, did your doctor advise you to do 100mg one day and then 50mg the next?
My understanding is that by changing your dosage in this way, you are putting your body in a constant state of flux whilst it tries to readjust to the different levels, hence the headaches. Coming off sertaline is not pleasant but can be made easier if done correctly. Tapering should be done by first decreasing the dosage until you reach 50mg, then the frequency, missing more days as time goes on.
The reason you can reduce from 50mg to nothing by gradually changing the frequency is because 50mg is such a low dose your body can handle it - this is why there is no 25mg tablet available, it would have no significant effect either way.
By reducing your dose you may find that your sex drive starts to return, when I stopped completely it returned fully. Unfortunately this didn’t aid conception and the stress eventually saw me needing sertaline again, this was 14months after stopping. I couldn’t believe after going through the awful side effects of stopping and then trying for so long without I was back to square one.
My doctor advised me that the risks during the first few months were slim and as I was only on 50mg slimmer still. To avoid withdrawal symptoms showing in the infant she advised tapering off them gradually before the third trimester, this way if I did need to start again I would only have been off them 6 months. Trying to stay off so long caused my mood and outlook, deteriorate along with my relationship.
My advice;
1) Check out this link regarding risks involved http://www.drugs.com/pregnancy/sertraline.html
2) Do not be pressured into coming off sertaline if you are not ready, look at the alternatives such reducing to 50mg and then reducing to nothing once pregnant. Alternative ask your doctor to prescribe a different drug, I can’t recall the name I tried another but it turned me into a zombie, you however may react differently.
3) Go to your doctor with a list of questions and make sure you get answers to them, so you can make an informed decision. My doctor got out books and we looked up certain information there and then. Better still, call your doctors and ask them to make you an appointment with somebody who knows about this stuff, I know there are 2 doctors at my surgery who have more experience in this area.
4) Get your boyfriend to go to the doctors with you so he can ask questions and get answers to any concerns. He needs to know what it is he asking you when he says he wants you to stop. You need to be working from the same page on this.
I hope I have made sense. Anything I have said should be checked with your doctor.
Best of luck!