Thanks for sharing your concern to Health Care Magic.
Prima facae, I would have pointed the diagnosis towards the heart problem. But since your EKG is absolutely normal, it is ruled out. In such case the second diagnosis that comes to my mind is
anaemia - less amount of
Haemoglobin in the blood.
Pregnancy as it is a state of blood dilution. During pregnancy, the total volume of blood increases, however, increase in the fluid content is more than the cellular content, thus the blood becomes dilute causing anaemia. Therefore there is increased need of iron and proteins during pregnancy. If your Haemoglobin is less than 10 gms %, such symptoms can occur.
During pregnancy, the increasing size of the uterus is putting pressure on the chest can sometimes give rise to such symptoms, particularly
tachycardia, breathlessness and
nausea appear. However, your blurry vision, slurry speech cannot be explained with this. I would advice you to show to a Consultant Obstetrician instead of just going to ER and getting emergency doctor's opinion.
If possible, please get your liver function tests done.