How to prevent going overboard?

just keep doing what you're doing. the debilitating injuries you're exposing yourself to will ensure that you get some rest days.

or....if you don't want to end up with a ton of overuse injuries, you'll use some common sense and slow down. there's a reason workout videos end.

Like everyone said, you're gonna do a lot more harm than good if you keep going like that.

You also shouldn't do HIIT more than three times a week (assuming you're doing it right) since your body needs to recover from it! Don't skip the cool down either.

I actually know the feeling, though, since I have a tendency to become overly motivated as well. What helps me is having a set programme that I follow. If I get into that 'over motivation' thinking, I then tell myself that the people who drew up the programme know what they're doing and definitely know more than I do about how to workout. Also, if I overdo it, my body will clearly tell me so after about a week by just not being able to push as hard as it usually can so listen to that feeling!
Personally, I'm doing Fitnessblender's eight week programme. If you're interested in heavy lifting, you could also have a look at the various programmes out there (New Rules of Lifting for Women and StrongLifts 5x5 are the ones I know), and I'm sure there are tons of other good structured workout programmes to pick from as well.

Like previous posters have said, you're setting yourself up for failure. At some point you'll just be exhausted or you'll injure yourself and you won't be able to exercise for a time. HIIT and weightlifting aren't things that should be done every day of the week (or even 5 days).

Maybe you can alternate HIIT and weight lifting days? Also don't skip the cooldown, it can prevent injury!

Also, if your shorts are 'pushing out' your lovehandles, it might just be time for a bigger size. Trying to squeeze into clothes that don't fit properly won't make you any happier, speaking from experience here (and not trying to be mean).

I am so not an expert, but I would suggest you try to focus a little more on your diet. You are working out a lot, but not seeing the fat loss you want. So switch it up. Pull back on your work outs a little and reduce your calorie intake. Focus on eating healthy and cut out as much crap as possible.

If it's the shorts-squeezing-love-handles-out problem that's spurring you on, buy bigger shorts!

Voices of reason. Figure maybe if I see other people tell me I'm overshotting it'd help since lord knows I won't trust my own opinion thinking it's just me being a slacker and wanting to give up.

You know the problem, it's up to you to work out how you can find something more sustainable. A sustainable objective really depends on knowing what you're trying to achieve, which I'm not convinced you have a handle on.

Weight loss comes from calorie deficit, not from exercise. Training helps you to gain flexibility around eating to your calorie deficit goal, and helps optimise your weight loss towards fat, by encouraging the retention of lean mass.

The initial HIIT tires me to the point I feel like I'm going to pass out. I do exactly what the trainer does except faster/more intensity/wider range depending on exercise, and atleast 1 extra movement more each set. Instead of a light shuffling in place like she does I jog in place. Not sure what more I can do to up the intensity.

OK, I watched the youtube video you posted, I'd describe that as a bodyweight circuit rather than HIIT, but that's kind of irrelevant right now.

What I would suggest is a combination of cardio work and resistance training of some kind. Beyond that it depends on what you want to do. Given that you're watching fitnessblender videos then I assume you're not a gym member, which isn't an issue.

Run, cycle, swim or something like that for your CV work, and find a bodyweight resistance plan, something like You Are Your Own Gym. Do three days per week of each and after a couple of months you should be seeing results, as long as you're eating in calorie deficit. Once you're there you'll be better placed to identify your longer term approach, whether that's improving your sports performance or increasing your resistance training.

5 minute break of vigorous pacing/power walk and I can do my general workout fairly easy afterwards.

The only reason I'm even doing the HIIT so much is because it's so short (less than 30 mins) and burns so many calories it's almost addicting.

fwiw a 25 minute tempo run will burn more than a 20 minute interval session. HIIT is not magic, despite what some advocate. It is very good for improving VO2Max, but you need to be really thrashing yourself in the intervals. For me that's in the order of 200-400 metre sprints at a 3-4 minute kilometre pace. No way I could sustain that pace for any longer as my normal aerobic pace is about 5:30-6 minute kilometre.