I took a 25 billion probiotic 2 days ago and my stomach has been hurting since(sore, bloated). is it unusual this would happen?

Any supplement can: Any supplement can cause a reaction because of the active or/and inactive ingredients. It is rare with probiotics. Stop the supplement.. If the symptoms resolve you can try another probiotic. Supplements or any natural healing modalities can cause "aggravation"/cleansing which is a healing reaction. In these cases Homeopathic Nux . V 12c can be helpful and safe also in pregnancy.