Not excited over engagement

My bf of 7 years proposed to me. And I had to fake the excitement. We went for dinner and took a walk and he asked wasn’t ntn super romantic or anything. I wasn’t expecting it at that moment but it was something I wanted with him. But during the moment it happened I wasn’t excited and I had to force tears that didn’t even come out. I’m so confused. I feel like I’m doubting our entire relationship. I’m a very sentimental person, I’m the person who sheds tears during movies over the smallest sort of affection and yet here in my moment I felt blank.

I should also add We’ve been engaged for about a month and I have made no effort to planning a wedding besides asking him what’s our budget and deciding we’ll get married in a particular month.