Hey Mel , if you want give up on that plant and get on a fast track to successful growing it's not going to be a problem...
There a few ,maybe ten simple steps , you have a space you have a great light , you have some skill since you got the plant this far ...
I'll tell you tomorrow what to do , any of the members can get you straight , don't be discouraged ....it's pretty simple once you commit to a few basic rules ...
Can you get some more seeds or clones to start ,? I guarantee a 100% turn around in no time , but get rid of that plant it's toast , the next one will be fine
Few basics you will nees
Adequate size pots for plant phases ...
Inline exhaust fan and ducting to cool your tube ( that's your biggest problem)
Small fan
Two timers
Promix and perlite bags or organic soil and perlite bags
Hand water mister
Dyna. Gro formula for veg and flower ...
You'll be amazed at what happens when the room temps are suitable
When the medium has proper drainage
When the plant if feeding correctly
Your gonna kill it , get seeds , get clones, start fresh .....thank me later