If you get a certificate you're all clear. If you're really breathless and your heart is banging away you should get your iron checked. Mine was really low a couple of months ago and I had lots of trouble catching my breath and thought my heart was going to jump out of my chest it was pumping so hard! I still get a bit breathless now but it's more squishing of my lungs by bub. You'll feel exhausted too with anaemia. But still take the time off and rest if you need it you don't want to run yourself right down