Ups & Downs

How come, everytime you feel everything is going your way and that all the pieces in your life seem to be in place, someone or something brings it back down. For example. Me and my girlfriend have been together for eight years. But ever since I got this job we have been fighting. She spends a lot of time whith her friends while I work and when I get home she isn't home. I thought we were able to figure out a arraingment of some kind as too how to deal with this. I want to see her when I'm home. I don't care what she does when I'm at work unless something needs to be done. As long as we both let each other know what and where we are doing. it is all ok. But recently she has decided to not tell me where she is going and using the excuse that she told me. or just straight out not say anyhthing. When I have to go do something I let her know. She know I go to the gym, I get medicine, I sometime eat out. I will go to my friends work and so on. But twice she has decided not to tell me she was going somewhere after work or even during the day. And one day she told me she was going somewhere only after I asked her if she wanted to go somewhere with me. Am I wrong into thinking that after eight years of doing something that she should be able to do this. I knew she was going to someones house, because she had a DVD by her clothes, but she still could of told me. I tell her. and now I feel sad. Sad that I might not be able to trust her. Why is she hiding. I thought we were doing so much better. I had a great time when we went to Disneyland and she told me she did also. But yet she does this. I'm at a lost of thinking. I don't know what to say or do. I'm going to have to talk to her. and then she will tell me I'm overreacting. I don't think so but she will tell me I am. More to come when I talk to her...