Atimos Modulite

Hi, I'm new here so don't know if this has already been discussed but I couldn't find anything on it. I received a letter from my doctor a while back saying the goverment had switched from prescribing Serevent to Atimos. I hadn't finished the Serevent I was using and had another lined up so it's only now I've had to make the swtich. I had one puff this morning and within minutes I'm shaking like a jelly. Is this normal? Did anyone else have this and does it wear off with use. I feel like I've had several puffs of ventolin. This stuff must be very strong.

Anyone know why this change was made?