how likely is it? :/

how likely is it to get pregnant again four weeks after having a baby...and having a normal period?

Pretty likely. You're very fertile after giving birth.

After having a baby you are at your most fertile peak. My sisters kids are 9 months apart, trust me it is true. My brother and I am 10 months. Listen to doctors when they say don't have sex for 6 weeks. Best of Luck.

If you're having unprotected sex, very likely. You are extremely fertile after birth, especially of you're not bfing.

Quoting Chelsea Dawn Moore:" how likely is it to get pregnant again four weeks after having a baby...and having a normal period?"

If you have sex it's likely. After you have a baby you are EXTREMELY fertile and more than likely to conceive again of you have unprotected sex. SIL had a baby and exactly 6 weeks later was pregnant again, so she would've had sex on the 4th PP week. Now she has two kids who are pretty much just over a year old.

very likely my family has several sets of Irish twins

Very. I always had my period a month after giving birth with all three of mine. Which means I had already ovulated between birth and a month later. But I always waited the recommended 6-8 weeks before any intercourse. It's a health/safety issue.