So glad to hear that Sam is doing well.
Although my wife and I did not have issues with prematurity, we did have issues with post-partum preeclampsia, one week and five weeks after delivery. I'm glad that you're going to be seeing her doctor soon, and please tell the doctor any concerns that you and your wife may have. Concern about heart attacks and/or anxiety will hopefully be taken seriously and the doctor will give you the gift of peace of mind.
Again, I'm not a doctor myself, but preeclampsia does happen post-partum--my wife was five weeks post-partum (like yours) when one of her bouts hit, and it was worse than the one week post-partum bout. I'm glad to see that she's checking her pressures. If I were you, I'd show the pressures to the doctor and tell him or her every concern that you have. Each case is different; my wife was put on nifedipine which brought pressures right down to a little bit below 120/80 from ~200/110. Her perinatologist also ran blood tests and 24 hour urine tests to check her kidney and liver functions, and her cuff was checking the pressures about every 15 minutes in the hospital. They also checked her eyes and her reflexes.
Hopefully your wife won't have to be admitted as mine was. As a concerned husband, I know that it's hard not knowing exactly what is going on, and hopefully your doctor will not leave a single stone unturned, give you peace of mind, and ensure that what he or she does leaves your wife feeling better with lower blood pressures.
Thanks for checking in; keeping all three of you in our thoughts and prayers for improved health and peace of mind from her doctor. I know that the schedule is hectic to say the least, please try to take care of yourself. It will give you more strength to help your wife and son.