DHA & EPA Alternatives

Is anyone else out there that is allergic to seafood and fish oils that take non DHA prenatals and get the right amount of Omega 3's another way? My friend said there are plant-based prenatals that have them in it but they are expensive and I like the prenatals I have because they are cheap with my insurance. Currently I use flaxseed and chia in a lot of my recipes and smoothies, and I also eat pretty healthy. Is this enough? How does everyone else supplement for DHA?

Background - TTC for a year, miscarried, TTC for another 2 years, just had HSG this cycle. Never changed prenatals, I've asked if I should and multiple Drs have told me there's no need. Virtus PrePlus tablets is the brand I use.