No movement at 18w

Hi ladies. I had been feeling movement since about 16w and my partner thought he felt a kick so but for the last week I don't feel like I've felt any movement at all. I'm a biggish girl so don't know if that makes a difference. I know that with your first you can feel movement from anytime between 18w and 20w it's just because I'm sure I felt a lot of movement before. Have any of you had this experience and everything been ok?