Vitamin D and K

I remember reading recently a post about Vitamin D, but i need some clarification. So if someone could help i would appreciate it.

I was diagnosed with low Vitamin D about a year ago. Doc (GP/Cardio) put me on 1000 mg supplements and did not specify whether to take D or D3. I don't remember which i took, but it worked, i retested after 3 months and i was normal (low end of normal range).
I decided on my own, about 3 months ago, to buy supplements from a company called Designs for Health (online) which was recommended by my Uro, for some other supplements he asked me to take. And, again, on my own, i decided to get the 5000 mg supplements, which i take daily. It is Vitamin D, with K1 and K2. It is NOT Vitamin D-3.
So i guess my questions are
1. should i be taking D-3?
2. Can i be harming myself by taking 5000MG?
3. What about the K-1 and K-2

All this supplement stuff is very confusing to me. My Uro believes in, practices and has conducted studies on it. And now with this Fish Oil issue, its putting a spotlight on the whole supplement thing, for me, at least.

I was told that D-3 is easier for the body to use. Never asked further. Doc told me to take it, and it is on my current meds list.

Can't say I know about K-1, but in the naturopathic circles I was told to take K-2 daily, which is supposed to help calcium be better absorbed by the bones. That was suggested by a doctor who thinks Prolia/Xgeva are not good choices.

I too am on a D-3 and K-2 and probably something else with a dash 1:}