trainers/behavourists, help please.

[ditavonteesed]

cherry became quite dog aggresive a while ago after being bitten by a larger dog, I got a trainer in and she showed me lots of positive things to do and she was back to herself after a few weeks.
Anyway, she is always a bit funny with other terriers so i tend to just avoid situations with other terriers.
When we went on holiday she stayed with my friend and went for a dog, catching the dog in the nose, this is the first time she had actually caught another dog. She was on the lead at the time.
She seems to have a big problem with leads and other dogs, wither if she is on the lead or the other dog is.
We have had a puppy for 2 weeks and she has been fabtastic with the puppy, never showing any aggression at all and playing with him all the time.
this week every walk we have been on has involved some sort of incident, first time a miniture dashund approached her while she was on lead and she went for it, obviously she was on lead and I was able to control her.
tues we went to a common, she was fine with most of the dogs we met, then we walked through a large number of dogs all the owners stood chatting, she approached an owner and a staffie puppy went for her, shhe turned back on him, but stopped immediatly went I shouted. a moment later as we were walking away a jack russell came running up and mounted her, she snapped at him but then they proceeded to run in circles for a while.
Today we were walking through the park and she was playing with a ball and a labradoodle, there was another dog approaching us on lead and friend with labradoodle says oh look its .... cherry ran staright up and went for dog, I called her back, put her on lead and kept her on lead, we then walked past another border terrier (she has always had a problem with other border terriers) and she started barking and pulling on the lead very aggresively.
I have called the trainer who came out in the first place and she is calling me back in the morning, in the mean time does anyone have any advice as I am rather worries about this again.
I know I must be doing something wrong but I dont know what, when it happened months ag i know I was rally nervous but I am not now so it cant be that.