Am I just being a jealous boyfriend?

I been dating a girl for about 7 months now. Its a long distance relationship that had trust issues at first because of her ex issues she lied about. Its been four and a half months since all that and i have not thrown it in het face at all since it happened but a little insecurity had always been in the back of my mind, but it has definitely gotten better. Our relationship configuraion is that we talk sevetal times eveyday if only briefly and text consistently. But....the other week, she went shopping in the early evening and said her phone was dying and she ended up staying out until 2 am and i had no idea where she was or if she was even safe...i was very upset because she was with a good friend of hers and when i asked why she didnt at least ask to use her phone to let me know she was ok, she said she didnt feel comfortable asking her which i said was bs because my girlfriend is the type to ask any perfect stranger any question...that really bothered me, so i had a long talk with her about making sure to do things for each other so we each will feel secure...and not a week later...she said she would call me when she got home from work, and said her phone was dying again, and i dony hear from her for 2 hours after she got off, and when i asked why, she said that it was because she was talking to some guy who was a regular customer at her store. (she is an assistant manager at walmart)...which sounded weird to me bc ive been shopping at walmart for years and never been personal friends with one of the employees...but she talked with this person outside the store for almost two hours....then the story changed to he used to work there and they would sometimes work together. The jealous bone is twitching inside me and she insists that its not a big deal but it bothets me...am i overreacting??