Is my gf cheating

My girlfriend and I have been dating for about 5 years. Lately I’ve started to notice odd behaviors and abrupt changes in schedule. She normally works part time and I pay all the bills. All of the sudden she’s working later working supposedly almost 6 days a week when she used to work like 3-4 5 hrs shifts. There is almost no sex in our relationship. She has become very distant and is almost never home and is either “working late” or hanging out with and friend or family. I have caught her in a few lies that she doesn’t know I know. One of the times she said she’s was working late and was going to meet her sister at the gym. I happened to have her sisters location on Snapchat and she was completely across town from the gym my gf said she was at.

Does this sound like cheating or am I just seeing things?