This problem is complicated, but well known,
Since 1998 all refined grains & flour have added folic acid (FA), by law. It has to do with neural tube defects. However, FA is not folate and is not L-5-methyl-folate which is what your body actually uses. FA is a synthetic and needs an extra handful of enzymatic steps to even begin to be used - more steps than folate needs.
As you consume pizza and refined breads/cereals the FA accumulates in your body and actually clogs the enzymatic pipeline to convert folate to L-5-methyl-folate. So, taking FA is counter-productive and can cause additional problems as mentioned.
You are better off consuming anything from the cabbage family, plus kale, and spinach. I like cole slaw.
Another approach is to supplement with methyl-folate and methyl-B12 together. This will help you get useful folate quicker and get around the clogged pipeline caused by FA. I like the Jarrow products, especially the 1000 mcg B12 with 400 mcg of Methyl Folate.
Its also possible that you have a common SNP on the MTHFR gene (C677t) which lowers your FA conversion efficiency by 75%.
Doctors rarely test for this mutation, but it will show up in a 23andme genomic medical profile.
Can you confirm that the anemia you have is macrocytic anemia, where the RBC size is too large and mis-shaped?
cheers,