Undecided

I went for a trail run Friday afternoon. My original plan was to go 12 miles. I started at 1:40pm. I took plenty of cold water with me, and a bottle of Gatorade. The trail is about 4 miles, so I thought I could loop it, and replenish my water, and not have to carry it all with me.
I made it about 1.77 miles, and had to stop and drink lots of water. I was so hot!! This is South Carolina so it gets hot quick. And, more than half the trail is fully exposed to the sun. I hadn't planned on that either. No sunscreen, and wearing a singlette. I'm so fair skinned, that I will burn like a fry. And I did. Last year I wore singlettes on the trails of Paris Mountain, and never once thought about sunscreen. So this took me by surprise.
Long story short, I only did 1 loop, and just added on 2 more miles back and forth in the shade.
But something occured to me while on this run. I have not acclimated to running in the heat yet. I've been running, but in the morning, when the sun isn't so strong.
So, I started thinking about the Chattooga River 50K race on June 8th. I'm not sure if I should do it. My longest run has been only 10 miles. My weekly mileage has not been consistent every week either. 14-24-9-30-11 each week. I've been so busy, that it was hard to fit my runs in. But even when I did the 30 mile week, I didn't feel any pain in my hamstring, or worn down. I felt great. Then I had 11 this past week. The race has not time limit, so my plan was to run/walk. I also thought I could at least try it, and drop if necessary.
It will also be hot during this race. I'm not sure how much of the trail is in the shade. But there are aid stations, and I will carry my energy drink with me. I will also apply plenty of sunscreen.
But there's an entirely different element to my decision for this race. June 8th is also the day my mother died, 8 years ago. It's also my younger sister's birthday. I had every intention of running this race in honor of them. That is very important to me.
So, with all this, I can't decide if I should do the race. I really do want to. I started to email the race director to tell her I would not be there, but I couldn't do it. I've already missed her first 2 races from this hamstring injury, and I just feel the need to do a race. But the question is SHOULD I do it.
My big goal race is Mountain Masochist 50 mile on November 1st. I DNF'd last year, and I have to conquer it this year. That is the biggest goal this year. My training will start right after the 50K on June 8th. I just hate to not do something, not knowing if I really could've finished it.
Anyone have thoughts about this? Any advise?

Cheri