WEANING OR NURSING?

I am nursing my 20 month-old and just found out there was a fetus in my womb.. my friend said it's dangerous to breastfeed while pregnant, not only for the fetus but also dangerous for my son.. it makes me confused.. one night, i was trying to wean my son when my mom was at home.. he went to bed with his grandma all night.. mom said he didn't drink anything.. when he was with my mom, i felt lonely.. i woke up many times and tought of him.. in the morning, after having breakfast, my son remembered breastfeeding.. he asked me to breastfeed him, and when i looked at his face.. oh my God.. what did i have to do? finally, i nursed him.. my effort to wean him was failed!
then, my mom went to Jakarta.. and i've not tried to wean him anymore..
When i surf internet, it is told It used to be felt that breastfeeding while pregnant can steal important nutrients from the fetus and can increase the risk of miscarriage. Now we know that this is not true. Many research studies have demonstrated no nutritional risk to the fetus, and no increased risk of miscarriage. Some experts encourage pregnant moms to continue to breastfeed as long as they want to.
There is, however, one situation where breastfeeding during pregnancy is NOT considered safe. For moms who have a history of miscarriages or preterm labor (labor beginning before 37 weeks gestation) with previous pregnancies, breastfeeding may increase the risk of these events occurring again. Why? Because breastfeeding releases a hormone into mom's bloodstream that can cause the uterus to contract. If a mom's uterus is especially sensitive to this hormone (i.e., if a mom has had preterm labor or miscarriages before) then breastfeeding MAY trigger the uterus to contract. However, most women's uteruses are NOT sensitive to this breastfeeding hormone. It is therefore safe to breastfeed during pregnancy. Alhamdulillah, I don't have miscarriage history..
some said, baby will be weaned by himself when the pregnancy goes 4-5 months.. because it produces colostrum for the new baby so the taste will be different as usual..
and now.. i am still confused.. must i continue breastfeeding or weaning him?