Sudden increase in movements

I am currently 33 weeks and suddenly my baby has been moving so much and so much stronger too, for the first time see him physically move around. I went to the hospital because I was worried he may be in distress because I couldn’t think of any other reason why fetal movements will suddenly be more frequent and suddenly stronger in one day. The midwives at the hospital put me on the CTG and monitored baby for 40 minutes and said everything seemed fine. Has anyone else experience sudden frequent movements?