4. Tiredness
Low blood pressure is often associated with anemia, which is caused by low red blood cells. Anemia can be the result itself of either low iron or low vitamin B12.
Either of these things prevents the blood from making enough red blood cells and that in turn means that you can end up not transporting enough oxygen around your body. This in turn can cause you to feel very tired and lethargic.
And even when this isn’t the issue, you can experience tiredness in association with low blood pressure because the blood won’t be making it around the body as well as it normally would do.