(((Bella12))) So sorry for what you are going through.
I can relate to what you are saying because I did similar things after discovery day (D-day). The term for this behavior is called hypervigilance and it is normal following a severe trauma, such as a betrayal by a loved one.
I would suggest you let your BF know you are struggling with this and allow him to help you by being patient with your need to know. Calmly communicate your concerns to him when you know you are feeling paranoia, instead of blowing up. I know he feels like the enemy sometimes, but if you can work together as a team, it will really help both of you rebuild emotional intimacy.
Regarding the anger from the past...This is also very normal. We all tend to hang onto anger when we believe the person that caused us the pain has not been punished enough or not done enough to mitigate the damage. The next time you feel angry, remind yourself of what is causing the anger, and try to have patience. Don't push away the anger, acknowledge it and the cause, and then tell yourself their are betters ways of dealing with anger than lashing out. Remember, we can't always control our thoughts, but we can control how we respond to them.
If the anger and hypervigilance continues to significantly interfere with your life and/or your relationship, it may be time to seek counseling. 5 months out can be a volatile time during R, so remember that patience and understanding are your key tools in R. Especially patience with yourself. It's ok to give yourself the precious gift of time to heal.