WHY am I gaining weight??

You know the same thing has been happening to me , i started workign out 5 times a week instead of 3 and i added more water to my diet and ive gained whats the scale says is like 3 or 4 pounds back i was floored and then started crying. After i had my moment i went and looked it up online and i guess its normal that when you work out alot your muscle hold water so try not to freak out to much , i know personally i drive myself nuts if i weigh in to much

could TOM be lurking around the corner?

Same thing happened to me this week. Monday morning I weighed myself and was up 5 lbs. This after 2 weeks of dropping about .5 lb/day. I've been at about 1500 calorie deficit the whole time, and then BAM up 5 lbs overnight.

It stayed on all week, too. I started freaking out, getting discouraged, and it started coming down a little bit, but I was pssed that it seemed like a wasted week....

Friday morning, BAM. 5 lbs gone. I'm now back to 3lbs lighter than I was Sunday morning (before the big jump on Monday), which is the .5lb/day that my deficit, etc. should have me at. Still right on track with just a weird bump this week.

Don't freak out, give it some time, and hopefully it will jump back down along with the weight that your deficit should have coming off as well.

Yes, I weigh myself naked every morning. GAH! I just don't even know where on Earth 2 pounds could come from! I am so frustrated because I seem to keep losing and gaining the same 2 pounds. I got down to 131, went back up to 133, got back down to 131, and now it's back!!! And for no obvious reason (like overeating). Seriously if it takes me all week to get back down to 131 I am going to cry. I want to see the 120's so bad, it's just a giant tease!

It is very likely water weight. Stop freaking out. A person's weight can vary several pounds because of thing that have nothing to do with fat, this is why the scale is such a back measure of success.

Question...how many calories do you eat daily? You said you ate an EXTRA 200-300 on the weekend, but were still under your net. Does that mean that you regularly eat 200-300 calories less than MFP tells you you should? Are we talking the original number they gave you, or including your exercise calories? If you aren't eating your exercise calories AND are stopping 2-300 short of your daily goal, then there's a very good chance your problems stem from not eating ENOUGH. It seems as though you have a pretty rigorous exercise schedule, so you really should be eating quite a bit. I know it seems counter-intuitive, but it really does help. You might gain for a week or 2, but then it'll start coming off again, and you'll have an easier time reaching the 120s. If you're going to train like an athlete you need to eat like one.

The healthiness of your meals won't make a difference if you're not getting enough calories, though you look like you have a great diet! On days where you run, do you eat your exercise calories? 23 miles a week would burn a lot of calories...and if you're not eating some or most of those back, then your deficit is too large..which would cause your weight loss to stall. I'm guessing you burn more than 400 calories during a 7 mile run, right? So even when you're eating 1600 calories, you're still not netting enough (you don't want to be lower than 1200 NET at the end of the day). If you try to add more calories into your day (extra protein shake, nuts, good fats, more snacks..) then you'll see improvements. At this point any strength training you do isn't really helping you because there's not enough fuel to go around in your body, so your muscles cannot build. If you eat more, you will notice improvements with your energy, muscle mass, and weight loss. It's just one more thing you can try if you find this plateau to be a persistent problem.