This is my third day in a row that I've struggled to complete the amount of running that I normally do....

I can't pinpoint why-- no particular fatigue or stress going on... I'm just having a tired week...

I can't believe I'm over-training-- I run 3-4 days in a row then take two or three days off (that's the only way my schedule works...)

Yesterday, I stopped after 25 minutes and went for a swim-- today 30 minutes felt like torture....

Should I take a day off?

I would. Your body is trying to tell you something.

Do you think you are catching a cold?

A.

I don't have any real advice, but I went through that a couple of weeks ago. Struggled with every run, had to stop and walk for a couple of minutes on a couple of them and just felt blah.
For me I was overtraining but mainly it was that I was bored with my workout routine. Do you run the same route everytime, at the same speed? Maybe try a different route or try running some intervals instead? Or maybe give running a miss for a few days and do something else instead, and you'll come back to it refreshed?
I did my first interval run on Tuesday and really enjoyed it. Today I'm going to try what they seem to call a long run, 5.5k at my steady pace, and see how that goes. Not looking forward to it as I get bored on the treadmill after 30mins, but going to give it a go.
Let me know how you get on.

You seem like you can read your body. I have a women's running book, and it says sometimes you just have days that are slower than others. Getting out there, even if you have to walk most of it, is better than not going at all, if you feel healthy. The easy days might prepare you for the best run you've had so far, and those days are really fun.

cue music. "Momma said there'd be days like this, there'd be days like this my Momma said".

Runners are always talking about bad weeks and good weeks.

I have good days and bad days, good weeks and less-good weeks, with my workouts too. For me, this is very much related to my calorie intake. A bigger deficit means less energy and reduced performance, but at a smaller deficit I can cope better. I do my workouts anyway, and forgive myself for often sucking at them; eventually when I don't need to create a calorie deficit in order to lose fat, then I'll function better at my workouts.

Last week I had a lazy week, I took it off, this week I'm fine... We can't aim for perfection all the time...

I always have crappy runs right before my period. If that is the case I just slow down and run through it.

If I have a tired day I just take the day off, but if after a couple days I am still feeling sluggish, I usually just push through.

the bad runs are partly what makes the good runs so good!

LOL. This must be true! I get a lot of so-so runs, and a bunch of crappy ones, but the good ones really are TERRIFIC.

I decided to take yesterday off because I had a long day with a lot of walking around.

So maybe today will be the good day! Weirdly enough last week the scale was stuck but my runs felt great, and this week I've been losing but tired on my runs... maybe there is a correlation.