33yrs old and don’t really exercise

I’m currently taking:

Omega 3
Vit E
& Prozac.

So far I feel great and the three don’t seem to be disagreeing with each other.

I was given a bottle of ‘Milk Thistle’ I was thinking about adding into my daily. When adding another supplement/vitamin into my daily how do I know if this is safe? Id like to also add something containing calcium as I don’t get much milk intake.(suggestions?)

Thank you

-Jay