Why do I feel like I need constant reurance of his love?

Sometimes my boyfriend and I will get into a small disagreement, but afterwards everything seems to be okay. However, the next day I wonder if he still loves me as much as he did before. I begin to overyze everything and read into everything too much. I keep thinking that things are small signs that he doesn't love me anymore. Then I fret and worry for a long time. Like last night, I had a stressful day and out of my frustration, I expressed disapproval at him for looking at . We resolved everything afterwards, but today I'm worried that he doesn't love me as much as before our spat. Today he left his computer on his login screen on although it says that he's logged in. Most of the time he just puts his computer asleep. So now I'm wondering if he's trying to send me signs and messages with his computer to express disapproval of our disagreement last night. I'm probably reading too much into it and worrying about it for no reason. I don't know why I always worry!