I had the flu jab whilst pregnant. The doctor told me they didn't really know for sure it was completely safe but suggested I weigh up the risks either way. Came to the same conclusion you did and had mine.
I've just had mine (24 weeks preg), like you I have one because I'm asthmatic.
The nurse at my doctors practice said they prefer not to offer the jab to a woman during the first 12 weeks of pregnancy, when the baby's vital bits and bobs are forming, but after that is fine. The World Health Organisation's advice is that all women, whether they've got a condition like asthma or not, should receive a flu jab, as your immune system is lowered during pregancy, so a dose of the flu is more likely to lead to complications.
I saw my GP (the whole surgery don't really inspire great confidence after he said that he thought that my blood glucose would be fine as "you look well"). I asked about flu jabs as had just been in the US and they recommend them for all pg women. He asked the nurse who agreed that is the recommendation and so I booked an appointment for next week and have just had her phone up to say that she is not prepared to give jab to pregnant woman!
How can she 'not be prepared to give to pregnant women' when if you read the leaflet that comes with the injection they recommend it be given to ALL pregnant women as immune system is low being pregnant. ARGH!!
WB - exactly my feeling. I am so cross about it at the moment. The whole surgery seems to be a complete shambles. Fortunately am moving in a couple of weeks and if I can't get any joy here will ask my new GP.
The NHS guidelines suggest it too. She is going to speak to the doctor and find another nurse who might be prepared to give it.