Same blood group will not cause any complication. Nausea and vomiting is the first 3 months of pregnqncy is common because of the hormone
beta hcg. if its excessive and you are not able to tolerate anything orally, you need to consult your doctor. Excessive vomiting is more common in multiple pregnancies like twins and triplets and another form of abnormal pregnancy called molar, so these should be ruled out by Ultrasound