S.L.
Oh man, you're lucky! I got my period back just months after my kids were born. Anyway, I remember that soon after my period came back, I had one that was late. I was so freaked out because I think the baby was only 5 months old. I was wondering how I was going to have another one, and what people would say when I had babies barely a year apart. I went and got a pregnancy test and took it. It was negative. I was relieved, but wondered why I was late.
Unfortunately, it started not too long after that, and man, it was a doozy! We were on vacation and I had cramps and felt icky and it was really heavy, so the vacation kinda sucked from there on out.
I don't think it's too abnormal to have things be a little irregular when they're just starting up again.
Good luck with TTC!