Advice

Kim • mom of two girls. 10/1/2011& 06/05/2018

So I had my lo 5 months ago. My periods have been coming between 21 and 30 days. Last month my so and I had sex the day b4 my period and now I haven't gotten one yet. Should I be concerned yet? Or is my body still trying to adjust to not being pregnant??? I'm having back and stomach cramps just no blood.