There has been no peer-reviewed studies, no clinical trials that show that a high protein diet prevents or cures preeclampsia. Brewers diet / blue ribbon baby is not based on sound science when it comes to preeclampsia. A healthy diet is important for all pregnant women, but diet has no bearing on preeclampsia.
Read this before you put your faith in the brewer diet: www.preeclampsia.org/forum/viewtopic.php?t=9742
The cause of preeclampsia is not known. Likely there are multiple causes, and it depends on the woman. Preeclampsia runs in families. Women with obesity, high blood pressure, and diabetes are at greater risk for preeclampsia, but once you have high blood pressure in pregnancy, the steps you would normally take for those problems are too little too late. There is no cure for preeclampsia except giving birth.
Medication is to be avoided in pregnancy, but high blood pressure can lead to preeclampsia, which can lead to premature birth, and serious health dangers to both mother and child. If preeclampsia occurs early in pregnancy, medication may be necessary to prevent premature birth. Each woman has to weigh the risks and talk to their doctor before they decide to take it, or not.
Exercise is good for pregnant women in general, but exercise does increase blood pressure in the short term. Take your blood pressure before and after exercise and see for yourself. Exercise during pregnancy does not prevent nor cure preeclampsia and can indeed make it worse. This is why bed rest is prescribed if you develop preeclampsia and for whatever reason cannot deliver immediately.
This post is not meant to scare the OP, but I believe knowledge is power. OP, there is nothing you could have done to prevent getting high blood pressure. It's not your fault. Keep taking your blood pressure, and if you can avoid a premature birth, your baby will be healthy and this will all become a distant memory soon.