fuel issue

Hi , can anyone help ,ive made this mistake before and got a response but I cant find it .I have a 1.8 8v gti sportline and decided to change my fuel filter [the large one next to the metering head] as my  car seems to be holding back when with a slight judder at around 70-80 mph but will go if you put your foot right down but I don't think that's correct .Any way I decided to change the filter ,I undone the 2 nuts either side got a slight burst of fuel come out as under pressure ,not sure that was very clever ! and I replaced the filter ,the new one went on empty I turned on the ignition after a few minutes tried to start it was struggling left it for half an hour then tried again it started but just about tick over if I touched the throttle it will cut out ,have I got air in the system ,does anyone know what silly mistake ive made don't want to mess around trying too guess what it is but I do recall having this issue a while back but cant think what I did to rectify it ,can anyone please help ..thank you pete

Fuel spraying out when undoing the filter is normal, next time just have a cloth over it and catch as much pertol as posible as its a great cleaner!
Have you put the filter on the right way round? there should be an arrow showing which way the fuel runs through. When the filter is put back on normal for it to take some time to start as the filter as to fill up again and they are large.
Picture to check which way you should have the filter, you can just see my battery in the left of the picture.

Hi ,thanks for replying the answer to your question is it is on the correct way round with the arrows in the same direction as petrol flow but what ive done since is got it just ticking over and undone one of the nuts again with a cloth covererd over that area cos of he amount of fuel coming also initially air bubbles but as i let it come out the engine started to tick over much better ,but at a point i stopped as i wanted to cllean up the area should i have carried on until i sounded like it was running ok? Ive since restarted it today and it still just about ticks over does that mean i have air lock somewhere…. thanks pete