If you have 'no reason not to trust her', but you are still jealous, then maybe you need to sort yourself out.
If she knows that you get jealous, and then she phones you while other boys are flirting with her, then maybe she needs to sort herself out.
If you both really care about each other, then you both need to sort yourselves and your relationship out.
I can certainly understand that you 'dont want her to get the idea that i will just jump for her' because you 'could potentially be a good thing in the far future'.
You need to discuss this seriously with her, I think. Sort out what you each want and need from this relationship. Make sure that no-one is making unreasonable demands or using the other.
Maybe, if the relationship is worth saving, get some relationship counselling.