Dying Leaves - Need Diagnosis

A good amount of leaves have black/brownish dying tips, the leaves have black spots, and some oranging dead spots on the leaf. To me that sounds like over-fertilization, but the red stems makes it seem as if it was a nitrogen deficiency or some other nutrient deficiency. Also I just noticed some of the bud hairs on 1 branch are reddish now, I think they're dying, and some leaves curl downwards a little bit, again made me think its over fertilization but I didn't know necrosis was caused from it too...? Anyone have any thoughts? Thanks

EDIT: Also, its about 3 weeks into flowering
EDIT2: Bud picture is from a week ago when it was healthy, and the overall plant picture is from 2 weeks ago when it was still healthy
EDIT3: Strain is White Widow if it matters / anyone cares