Liquorice - one of the causes of being run down and being very susceptible to "bugs" is being low in Vitamin D. In the wintertime , we cannot make vitamin D in our skin, our store drops , and we become even more susceptible.
If I was you , I would get myself tested for vitamin D deficiency. It is very common in Britain , especially if you are not outdoors , in the sun a bit.( without sunscreen for at least 20 mins ). Sunscreen stops you making Vit D in the skin. In Britain , you cannot make vit D between October and March, the sunlight is too weak.
Even in the summer months , the required UVB in sunlight is only there between 10 am and 3 pm. We do get a little bit from food, but not nearly enough. Oily fish like salmon is probably the best source, but farmed salmon only has 1/4 the level of wild salmon. i.e. very little.
There is not a consensus about what is a healthy level of vitamin D among medical professionals. There is lots of evidence now that we need more than currently thought. In the UK , NHS guidlines say that 50 is ok, anything below that is either insufficiency , or deficiency, according to your exact level.
Your doctor may let you have a test if you ask him, let him know about your troubles ! IF your doctor is unco-operative , you can get a paid for test from an NHS lab , by post from Sandwell, Dudley NHS Path Lab. They charge £28 . It can be ordered over the phone by credit card. It entails a finger prick, and you sending back a sample on a blotting paper to the lab. They email your result within a week. Visit www.vitamindtest.org.uk to order a pack. You can order on 0121 507 4278 as well.
To supplement with Vit D is very easy and cheap, it is the cheapest vitamin to buy , especially on amazon etc.
I have posted on this topic on other threads , see
www.mumsnet.com/Talk/general_health/2376645-Hospital-wouldnt-test-me-for-vitamin-D
and others.
Hope this helps. Good Luck
BTBH