@Kaylz - If you haven't been outdoors for almost a year, it's odds-on your Vitamin D will be low, if not very low.
I have my Vit D tracked because of my thyroid issues, so I have a handle on what's going on. I supplement throughout the year, although in the summer I reduce the dose. Many stop supplementing in summer, but because I have thyroid issues, it is important to keep my levels in a good place.
In your shoes, I would consider these:
https://www.amazon.co.uk/Vitamin-D3...=vitamin+k2&sprefix=vitamin+d3,aps,178&sr=8-2
£5.99 (delivered) for 3 months supply at a decent level, or this one, at just under £10, for a year:
I appreciate cash is tight for you, but Vitamin D is a cornerstone to our metabolic and bone health, and the added K2 influenced the take-up of calcium to our bones, rather than sloshing around in our systems.
Vitamin D levels have also been found to be influencial in how someone copes with COVID, if they are unfortunate enough to contract it.
We have also been taking 1gr Vitamin C per day; not because we think we are deficient, but because it also seems to positively impact on coping with COVID. (Any excess VitC is just passed in urine, so it's a low risk strategy, in my opinion.)
And finally, we also supplement magnesium. It is understood to help with sleep. I have always slept well, but my OH has a history of night time waking, which this has helped. As I understand it, there is no reliable test for magnesium levels. Getting the right magnesium for any given individual can be time consuming (in terms of reading), so maybe one to put on the back burner for now, unless you suffer with cramps, tingling or numbness, in which case, it's time to see the Doc or do some reading on supplementing.
As I say, that's my approach.