Bf randomly withdraws / shuts down and then shuts me out, normal or not?

My bf will randomly get into these moods where he becomes withdrawn and not affectionate and it’s happened over time so much that I can tell exactly when it’s happening cause he gets this look on his face and either asks to be alone. During these moods he stops being affectionate in all ways , and sometimes will just straight up ignore me / pull away when I go toward him before he asks for space / tells me to leave. I respect that and do that when asked but sometimes I ask “are you upset with me” and ask for reassurance cause it genuinely gives me anxiety and confuses the heck out of me. The pattern is he does this and a day later or 2 he will be completely back to normal and very affectionate and in a much better mood. But it’s been 2-3 weeks without an episode like this so it’s been a nice long stretch (for us). Anyway he invited me over last night and when we got into bed I could tell his withdrawn mood was coming cause he went silent and didn’t say goodbye, and was on the opposite side of the bed as me. He kept sighing and I asked if he’s okay and he just mumbled “yea.” In the morning I tried to put a light hand on him to reach for connection again and he just moved away. I didn’t try again. Anyway, we got ready for work and went downstairs to depart, and typically we kiss and say goodbye but he just started walking off and I said “bye !!” Quickly trying to reach to him and he barely looked back and mumbled and kept walking. Everytime it happens I can’t but help blame myself. Before bed last night I knew it wasn’t my fault and was like “whatever I’ll leave him alone it’s his problem “ but after this morning I’m in an anxiety spiral and just feel shitty. And it makes me mad he treats me like this when he shuts down. If I didn’t cause it why treat me like that? When I’m upset I seek affection but he’s clearly the opposite. Are any of you guys like this? If you are can you explain what’s going thru your head in these moments? Do you know you’re hurting the other person by this? Do you not care? Or can you not control it? I jusy don’t understand when he acts like this