It could be that your Neurologist will make his decision depending on how your symptoms have been since the Lp. If the Lp has failed to control your pressure and medication cann't be used, he may decide a shunt is the best option for you.
Pregnancy can elevate your pressure, and in some cases such as my own, it can trigger IIH. Your Neurologist will have taken that into account, and his main treatment plan will be to alleviate your symptoms, lower your pressure and most of all maintain your vision. As you are allergic to the IIH medication he has to look at the other options which may be surgery. We have a Guide sheet that helps you to talk to your Doctor and Neurosurgeon and includes the kind of questions you can ask him. Here are the links;
Talking to your Doctor about IIH
Talking to your Neurosurgeon about IIH surgery
I'm sure your Doctor will help you, and if he cann't, will recommend or refer you to someone who can. As you are having headaches and your vision is compromised he cann't leave you untreated. Once he has you on the right track treatment wise, you will be able to function a lot better and be able to care for your son. I too had IIH with a young baby, and once I was on the right treatment plan was able to care for her and do things with her.
Keep strong and most of all determined. Ask your Doctor/ Neurosurgeon as many questions as you need to before you make any decisions yourself. The more information you have the better, and if you can take either your partner, relative or a good friend with you for support, and who can also ask questions that maybe you didn't think of.
We're here to support and help you, and encourage you to have a better life with IIH.