@turquoise-- That happened to me as well when I first started using these medications. I was extremely tired. But after the first month, this side effect lessened considerably. I'm now mostly fine.
I think that fatigue is not only due to the medications but due to the change in blood pressure. If the body was used to higher blood pressure rates, it will take some time for it to adjust to lower blood pressure. So the fatigue might just be a sign that your body hasn't adjusted yet.
If this side effect doesn't wear off after a few weeks though, then you should talk to your doctor about it. Speak to your doctor sooner if other side effects develop.