breathlessness issues

So 3 weeks ago I had a 5 day hospital stay due to extreme breathlessness. I'm currently signed off work. I had stays, a vg scan, 6 ecgs, and hooked up to a telemetry machine. Apart from my heart rate being high, lowest recorded in last 3 weeks is 96. it's been as high as 120. No-one, not even the midwife wants to call it pregnancy related. I've made another doc appointment today as I'm unable to walk up the stairs without getting short of breath and dizzy. I can't walk round the supermarket without sitting down a dozen times. To shower I have to have a stool to sit on and prioritise what needs done most, so currently my legs look like they belong to a monkey! Anyone else been in a similar situation?