Please keep me sane

I know you probably see similar posts like this dozens of times, but... 

Over the past week DD, who is 7 mos, has been teething and as a result she isn't nursing like she was.  She eats, but not as frequently as she usually does.  Sometimes she'll latch on and then pop off right away because she is in pain.  

Prior to this I was extremely paranoid about my supply.  Its taking longer and longer for let down, which is frustrating for DD.  I'm under a lot of stress from work and many days I stay up late working from home trying to catch up.  I'm eating oatmeal, taking fenugreek...trying to eat and drink as much as I can but I definitely am not taking as good care of myself as I need to be.   

DD won't take a bottle, but will take a sippy cup.  She's eating solids, but not much - maybe half an ounce of oatmeal in the afternoon and half an ounce to an ounce of vegetables at night.

Since she is having issues latching, I tried pumping after she skipped a feeding so that I could give it to her in the sippy cup.  I got a few drops out but that's it.

I need to know what I can do to ensure my supply doesn't dry up completely.  I am terrified that I am drying up because of this stress from work and lack of sleep.  I am trying to take good care of myself as best I can and I have made a conscious decision that going forward I will go to bed earlier and if I can't catch up with work then so be it.

How do I know for sure if my supply is drying up?  How can I tell - is the longer let down and inability to pump at an expected feeding a sign?   Will more frequent pumping sessions bring my supply back up?  I'm just so worried that I am losing my supply and I won't be able to get it back.  I am so stressed about this, I feel like it is just exacerbating the issue.

I'm sorry if this post is all over the place.