Definitely speak to her man - don't listen to others on this thread as it's very easy to post annonymously on the internet regarding other people's issues but not so easy when things like this are actually happening to you.
You're clearly quite sensitive about it which is good and bad. It's good that you obviously had a good weekend with her and clearly care for her etc but its bad that you are doing the typical human thing of letting your emotions override your rational judgment. This might sound odd at first but I would recommend martial arts. I myself am (or was) hyper sensitive but have been training for a while now and the human 'spirit' is an amazing thing ONCE you gain respect for yourself and what discipline you can apply to your being introspectively.
You are quite right that you shouldn't have been treated like that but conversely, there might be a much more innocent reason to your evacuation...such as embarrassment? Obviously you have more of an insight into her relationship with her mum than we do on here but might it be that they just don't have a close relationship and therefore don't feel comfortable disclosing much to each other? Of course, it could be the complete opposite or something totally unrelated. However, either way you must try and be calm and composed without letting your emotions take rule of your decision making...again, I would recommend training. People think martial arts is just a physical thing - it is so much more. Please note, I didnt read all of the thread (just page 1) so ignore this post if everything's been sorted already.
Tom