After that first period, I did not get another

Hi,
Welcome to the ehealthforum. I am glad to help you out. You seem to be having lactational amenorrhea.

So chances of pregnancy are less but not impossible. It suppresses ovulation because suckling (breast feeding by the baby) changes the body's physiology so that ovulation does not occur.

But sometimes ovulation may return prior to menstrual periods after delivery and having unprotected intercourse may result in pregnancy. I'll suggest you to practice safe sex in future too by asking your partner to use condoms.

It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.