Girls need advice! My cycle has returned after childbirth! It's been …

Girls need advice! My cycle has returned after childbirth! It's been normal for 5-6 months now! But every two months, they start 5-6 days earlier, with no signs of them at all. In September, from the 24th to the 25th, I had sex with my husband and it was in me (from night until morning, everything was normal, in the evening they were not very strong, 3 days and it ended!) I really want sweet things, I started gaining weight, I weighed 45 then now 51, with a height of 150 I even started exercising In October, from the 21st