Period

Hi guys,

Need help! I was on the pill for a very long time started when I was 11 now 22. I came of the pill when I was 21 to try for baby. I had one period and fell pregnant instantly! I gave birth via c section due to placenta being in the way. My little boy came 2 weeks early. I lost a lot of blood during the procedure. However, I'm currently nearly 4 months post c section and no sign of a period! Is this normal? I'm getting horrible pains like I did when I found out I was pregnant- tests negative. Anyone know how much longer I should wait before worrying? Thanks in advance