I bonked and I don't know why?

Tonight I did a 50 minute bike ride and not at a crazy pace but a good pace for me I did about 13.5 miles.  I then followed that with a brick run which was supposed to be a 5k.  I started out the run feeling good and strong but about 2 miles in I started feeling weird, I pushed on for another half mile but I was a bit light headed and my legs just didn't want to go.  My heart rate was about 160 (which is not high for me), I wasn't out of breath and my legs weren't burning they just sort of felt rubbery and I couldn't go on.

I'm assuming this was a bonk but the weird thing is I ate an Oh Yeah! bar (grab bar, not a full) about 30 minutes before the bike ride and I also ate a packet of sport beans on the bike ride so I'm not sure why I would Bonk?

I ate mostly protein earlier in the day but did have some watermelon.  I consumed about 500 calories before eating the Oh Yeah! and the sports beans which added another 290 calories with a lot of carbs.  Could it be I didn't have enough calories before the workout?

Could it have been something else?  I did a practice Triathlon Sunday morning that was just a bit shorter that the Sprint I'm training for and did well.   I took yesterday as a total rest day and I felt good today so I think I was rested?

I don't think you bonked...although you need more calories.

You think you had a bout of reactive hypoglycemia?

Well I looked it up and reactive hypoglycemia sounds very similar to bonking so maybe but don't know why that would have happened either.  I sounds like dumping might cause it but the few times I've dumped from eating something rich and very high in sugar I had a serious bout of the bots, which was not the case this time.

Who knows, I just hope it doesn't happen during the race.  I'll be sure to eat enough the 2 days before and have a decent breakfast about 3 hours prior.

My symptoms for dumping and hypo are totally different. I feel sick when I dump. I feel dizzy/lightheaded when I have hypo. With my hypo the same things don't always cause it. It's almost random. Make sure to eat some form of protein along w/your simple carbs.

I would eat maybe 2 hours before-3 seems a bit far away.

If you can tolerate gels, I take one 15 minutes before the swim.

Yes I tolerate GU well.  The one thing I did different in my workout last night was I used the Sports beans instead of GU.  I like the beans better from a taste standpoint but although it seems odd maybe they just didn't agree with me. 

On race day I thought I'd probably eat something around 5:45 am, a ww muffin with peanut butter, honey and half a banana.  My swim wave will be last or 2nd to last because I am doing a "buddy" wave and was told we go at the very end so it won't go until 9 am'ish (first wave is at 8, waves are 100 people, and there are 2000 doing the race).  So, I thought I eat the other half a banana around 7:45.  Then a GU in T1 and a GU in T2.

But, maybe it would be better to eat a GU right before I swim, close to 9 am and another in  T1 or 15 minutes into the bike ride.

I figure the swim will take me no more than a half hour at the most, the bike no more than an hour and the run around 35-40 minutes.  Those should be my longest times and hopefully I'll do better but I am doing it with a friend and she wants to stick together.  She hasn't been able to train nearly as much as I.  She's a natural athlete and competitive so hopefully we will be at the same pace.

When I got my mileage up to 8-10 miles at a time, I found I had to adjust my diet to add more carbs and such that I got carbs before workout/training and protein after.  I still kept proten intake at 180-200 mgs a day so I had to watch my caloric intake that got me when I hurt my hip and wound up taking a total of 8 months off before i was able to restart running. 
I found the spots beans work for me on the road but I agree with the bonked feeling, sounds like my experience when the body is finished whether you want it to be or not.

I also, my opinion, think that while there is science involved and ways to combat it, it is just the process of the body hitting wal of being outof gas/max capacity and our training the body to do more better than it is use to performing.  So I write it off as progress,...taking it to the next level you've haven't reached before.

Hows that for the glass being half full?

Fall back, regroup , and move forward; one step back, two steps forward.

How was your hydration going into the workout?  I find that a little dehydration impacts my workouts worse than not having enough calories.

Cassie