First enticer tri done but I've hit a slump

On Sunday I completed my first enticer tri of the season.

300swim/8km ride/3km run 

I did it in 49min in the end including transition which I am happy about. Being my first back an having only had a baby in march that's pretty good. 

Times wise I did 6:29min/20min/20:03min

The swim could have been better it was in a pool and I kept getting stuck behind slow people and having to over take them. 

The girl who came first did the times I would normally in a training session. My issue was the heat. I'm used to training at 5-6am this was at 8:30-9:30 and it was a hot day. 

The next one is in 8 weeks so it will be even hotter but I'm going to start training harder. 

So then comes the slump. It doesn't help I'm sick. I woke up with it the day before the tri :( it's just a cold but it's crap. It comes with a killer headache I just can't ditch and I'm so bloody tired. My body just feels exhausted. The boys have it too so they are miserable which adds to my exhaustion. 

My diet isn't 100% but it's not bad. I'm just mindlessly snacking. If I had the energy I would do a quick calorie count. Problem is I have plateaued in my weight loss and it's annoying me. I still have 10-15lg to lose easily. I'm working out 1 1/2 hours a day.y diet is 90% good. I know plateaues happen and u do eventually break through but they are certainly frustrating. 

How do I reel my mind back in? I'm struggling at the weight training bit but I think that's because I have upped my cardio so much. I'm doing that for the triathlons. I really enjoy cardio. I know most people don't but I do. I'm not enjoying the weights but is that simply just because I'm too tired? 

Then there is maybe I'm not fueling right? Maybe I'm not getting enough fuel for everything I'm doing? Then again I am sick and perhaps over thinking this. 

I need to sit down and reassess and refocus. Look at what I'm doing and what needs to change. Hopefully this cold thing passes soon.