Iron deficiency

[AllBranEater]

Firstly, I do have a GP appointment booked. My results are as follows:
Transferrin saturation index 7 % 16 - 50
Serum transferrin 3.63 g/L 1.8 - 3.6
Serum iron level 5.9 micromol/L 11 - 30
Serum ferritin 12.2 microg/L 30 - 336
I understand that these mean iron deficiency, but how serious? I do feel fairly awful...are they likely to suggest iron tablets?

Yes probably will suggest iron tablets. I'm chronically anemic and my most recent blood tests are worse than yours, but mine are very low all of the time. I take a high dose of iron daily whilst I'm waiting for further investigation, this has been going on for at least 15 years for me though.