Maybe it was guttate? It looks like someone splattered you with red paint. pustular would be quite surprising and I expect would be taken pretty seriously.
First thing is to find a good emollient that feels comfortable on your skin. Alternatives to aqueous cream are things like diprobase, e45, oilatum, aveeno (sme of those go in the bath) Emollients are the basis of your treatment.
Second, have you had any throat or skin infections recently? Strep in particular can trigger psoriasis, particularly guttate. My dermatolgist says its important that I do take antibiotics at the first hint of a bacterial infection. More and more gps are starting to follow that with me. (I've had almost life long severe psoriasis)
Remember not to scratch or pick at it. That will almost certainly prolong it or even worsen it.
If it continues to spread or doesnt improve with the above then there are plenty of next line treatments.
Coal tar derivatives are a bit smelly to use but effective.
Then for larger patches theres dovonex. Many people find that really really effective.
Take care with steroid creams. You musn't use them long term but they can be great for getting on top of an attack short term.
UV treatment is good, but can be hard to get.
I recommend getting a pre-payment certificate so that you can try different thiongs without worrying about how much it will cost you. If you haven't got a sympathetic gp and can't persuade them to treat you properly then ask for a dermatologist referral.