I'm 3 months postnatal (second baby) and my fitness has always been okish. I started doing some DVDs in the evening to begin the long process of getting my body back. But every time I'm half way through I begin trembling and get really hot and need to throw up. A bit of bread quickly eases the nausea but the shaking stays for ages. I'm not doing any particularly strenuous exercises that are making my muscles shake, it's the (even gentle) ones when my head is hanging over my body (when standing or on all fours) which is doing this. Do you think it's a weird blood pressure thing or something? Why is my body being unreasonable to me?!