Maybe you should be on a different med. I know that I had to change meds b/c it was not really controlling my BP's. I would get a new doc. I assume you have seen a cardiologist? I used to suffer from tachycardia too and had to wear a Queen of Hearts cardiac monitor for two weeks. We learned that I have a heart arrhythmia...nothing serious at this point in my life. I also used to get chronic migraines. But since I started Toperal and even the aldomet, I have not had one. BP meds can help with migraines.
PCOS is linked to high BP...I do not want to rain on any of your plans, but I would get your BP under control before getting pg. Sometimes diet and exercise can help with lowering your BP as well (in addition to meds). Get a new doc

Have you ever heard of Pre-eclampsia/eclampsia? We are at higher risk for this since we already have pre-existing HTN (even though some women can come off their meds during pg up until late 2nd tri or into 3rd trimester...this is about the time some women are Dx with PIH-pg induced HTN). You are at a higher risk since your BP is not well controlled.
Okay well getting of the soap box again...I really hope this helps and please get the BP under control! Is your thyroid under control?