My pregnancy was confirmed on 15 may 2025 and through pregnancy sac Dr said I am 5 weeks 2 days pregnant. On follow up check up on 24 may analysing through pregnancy sac it shows I am 5 weeks 6 days pregnant. According with my LMP it has to be 6 weeks 5 days. But my period cycle is not 28 days cycle. It may vary up to 35 days in some months. So is anything to worry. What could be the reason for slow progress?