PARENTS AND VEGANISM

I've been trying to become vegan (or at least vegetarian) for a few months now. I can't remember the last time I ate meat. There have been so many benefits so far - clear skin, more energy, no bloating or constipation and many more. However, my parents have been on my case basically from the start of it all. They go against anything I say and shut me down immediately every time I try to explain something. I just went to the doctors today to review some blood work that was done a few weeks ago. My iron and B12 were extremely low even though I've been eating tons of plant based foods that claimed we're rich in these nutrients. Now, my parents are even more worried and insist me eating meat again, period. My mom threatened and said if I resist then she'll admit me into a hospital. Again, I feel fine but my blood tests say otherwise which is frustrating especially since I thought I was doing so well :( my doctor said that he can try to find me a nutritionist to talk to and if I wanted to I could take supplements (but supplements leave me constipated and I'm not 100% ok with them). I'm old enough to make my own decisions but my parents are on my case about everything and idk what to do/tell them with this whole situation. I really don't want to go back to eating meat :(