Losing my girlfriend to J1 visa trip?

My girlfriend left for the states on a J1 for 2 months. She was never looking forward to going and didnt wanna leave when the time came. We're crazy about each other but I promised her things would be ok. For the first week she said she didnt like it and missed me too much. The second week she was ok and started to settle in so i was happy if she was. We only get to talk when we text at night and its a five hour difference from where she is. But lately shes been different. She hasnt texted back a lot at all and doesnt seem bothered if she forgot. Ive noticed little things that only a boyfriend would notice and I know things are changing or fading. I suffer from depression because its hereditary in my family and I know sometimes it clouds my judgement on things but im generally worried now and am afraid of any confrontation in case my fears are true :( Any advice or even just someone that can relate would be greatly appreciated