I am just wondering how out of breath is normal for pregnancy??

I am almost 24 weeks now and for many weeks i've been very breathless, for instance even just hanging out the washing, checking the mail, or sometimes walking to the kitchen, i am panting for breath. I have also had chest tightenings and it feels like my heart is racing - but i thought this was related to my anxiety and i am currently trialling treatment for that. The anxiety is better but i'm still getting the chest tightenings and breathless.

I don't remember having this in my last pregnancy unless i went for a long walk or some other exercise. I don't want to sound lazy but i'm certainly not exerting myself as i am home with my DS on a daily basis.

So would you say this is related to the anxiety or perhaps just normal as i know each pregancy is different?