Do I need an Omega-Three supplement if I use ground flaxseed daily?

Patient: I’m 17 weeks pregnant and vegan. Getting enough omega-3 for the baby has always been a concern for me so I have been adding a Tbsp of ground flaxseed to my morning smoothies or cereal every day. Is that enough or should I be taking a supplement as well? I’ve looked into Spectrum Essentials Prenatal DHA supplements but is it possible to get too much omega-3?