Oh no, the poor love. I have a young cocker who is the light of my life, so full of joy, and a sad spaniel is a very sad thing indeed.
It’s hard to advise from afar without seeing what thought process she’s having, but remember that she is extremely tiny. 14 weeks is still very young – indeed, is she not still in the socialisation period? We got our girl at 12 weeks and I definitely didn’t consider her socialisation period ‘over’ for at least two months after we got her as there was no way she could have met everything and every kind of person in such a short period of time.
As others have said, don’t pander to her concerns. Just walk on. She sees another dog, gets scared, don’t pick her up or fuss her, breeze on, nice and brisk – nothing to be scared of, all good. You want to build a positive association with things so she only has good encounters, so you spirit her away with a ball/treat reward/whatever works for her. Reward when she gets it ‘right’.
You need not to show your concerns too. You need to express precisely zero negative emotions to her about the things she is encountering and instead be confident – show her that it’s ok, that she is a big girl and she can do it. They know if we’re worried, especially if our voices give it away. If you tense up and she’s onlead, she’ll feel it down the line – and if you tense up every time you see a dog approaching and she’s on the lead, she’s going to associate a dog approaching with ‘oh no mum is worried’ and then she’ll be extra worried. You want to be happy, cheery, breezy instead even if it’s the opposite of how you feel.
Do these scary encounters happen when she’s on or offlead or both? Onlead encounters can be scary for already spooked pups as they can’t get away and that’s when some can become reactive, though you say she isn’t, which is good. There are various pattern games that you could look up that might work for this – they’re really good for getting a dog to focus on you when they need to.
If you live in Lincs you’re more than welcome to borrow my extremely polite, confident cocker to give her some positive associations with friendly but respectful dogs of her own breed.