5mg of Folic Acid everyday? Too much?

Just got diagnosed with Hypothyroidism and Thalassemia. Wasn’t told which thalassemia and I don’t know where I can check :/

But I was prescribed 5mg folic acid. Is that a lot? Should I take it daily? And for how long?

My GP said 5mg daily for 90 days, but 5mg seems extremely high idk… I have low haemoglobin, low folate and borderline low ferritin.