Dang, relax. That looks healthy enough. The new growth looks good. It's normal for a plant to use up older, lower leaves as it grows...

Dunno about the spots. Saw something like that once; it was from nutes getting splashed on the leaves.

If your pH is off, you could have a lockout. Get yourself some test strips or something--at some point you are going to need to know what your soil pH is anyway. Prolly now is that time.

Normally, a light feeding with a grow/veg fert (heavier on the N) wouldn't hurt anything. But if you're locked out it won't help / may make things worse. Did I mention you might wanna know what the soil pH is? :hippy: