think you maybe over night, I had exactly the same, felt like I was suffocating in it, had to get my mum to rush to asda to buy me a cheepy. My original one was a shockabsorber from Debenhams and cost me £30, Asda, Marks and Spencer are £12 and much more comfortable. After about 4/5 days I was blowing off(excuse me) like a gooden, think it was the pain killers really bunged me up, but after felt sooooooo much better and finally deflated alittle and could get the original back on, so it will settle down hun. happy healing x x x x x