I panic when pleasured. is it normal??

Ellie
So I've been with a guy for 5 months, still not done the deed and taking it slow. However, whenever he pleasures me through my breasts too much, I begin to panic and it hurts. 
Now he is extremely gentle with me and realises I get dizzy after a while. Today I had a panic attack when it happened. I don't understand why and I feel like I'm insulting him. He managed to calm me down (He's such a gentle guy honestly). 
Is it normal, this has been my first ever relationship so just adding that in.