From 155Lb to 159Lb in 4 days

Suky • Mama to be 😇 Mu little Rainbow 🌈 will be here in September 🐣 I love her already
Hi ladies, so last friday i weight 155Lb n yesterday i weight again 159Lb.  And today im 161Lb.  I did not get weight at all untill now at 28 weeks at first i lost weight cuz i was throwing up a lots ! Is this normal ?