2 week, 2 mistakes

Hi, recently i have restarted a relationship with my ex. We broke up last year for because she didnt feel as if things were progressing. Alot of it was my fault because i was hiding the fact that she was the only women id had ever been with, which made me nervous which i turn made things "not happen". About a month ago she came back stating she had made a mistake and would like to give it another shot. I was slightly skeptical but it didnt take much for me to agree. The first Three week were awesome a complete 360 from the last time we dated. Just this pass weekend was having a very out of character day, and made a comment about her job which she took the wrong way and really upset her. I felt like a complete jerk, didnt see her all week but kept maintain contact that i was really sorry and wasnt like me to do stuff like that. NOW yesterday i was hanging out with her all day, stuff was going good then at night she stepped out for a an hour or so and my friend ask if i would like to go the bar with him. At first i said no but upon a second try he managed to convince me to go. Just as i was leaving she came home, was extremely upset that was going out and that i hungout with her all day and then "ditched" her the second she was out of sight. I know i made a huge mistake wasnt really thinking, for some reason i thought she would be happy if she came home and i wasnt there. She is know understandably questioning the whole thing all over again. The fact that these two mistakes happened in such close proximity to each other is making me look horrible. I want nothing more then to stay with her, any advice on how to handle a situation like this? or am i doomed and just a big jerk and deserve what i have coming to me?

Also i notice yesterday after all this has happened that she is text messaging her ex boyfriend. Is this something i should bring up or just let it go for now, and its just a coincidence it happened at the same time.