Can someone please explain to me what's going on with my body?

I've been working out and eating healthy for the past month and a half now, and seeing some considerable results....i think i hit a plateau a little while ago, but then changed my workout routine. I also recently started using the rowing machine at the gym, which makes the muscles in my somach and arms incredibly sore.

My question is three days i weighed 147 pounds, then shot up to 151 pounds...which doesn't make sense since i've only been eating about 1500 calories a day...i figured it'd go away in a day or two, but it appears to be staying there! can anyone explain what's going on?

Is it near or around TTOM... Most women fluctuate greatly around that time...

Maybe you are building muscle... do you see/feel results?

It's either muscle from the rowing or fat from not eating enough... But I can't think of a way to tell for sure which?

How has your sodium (salt) been the last few days? Have you been drinking the recommended water for your size & weight?  Also, if you exercise regularly, you should not weigh yourself the same day as the exercising as your muscles expand during exercising (then contract as they "build & mend") so it is possible that the extra weight might be your muscles just doing what they need to because of the exercising.  Also, as others mentioned, maybe it's close to TTOM?  Could be any number of reasons.

nope, TTOM isn't until about 2 weeks...

i've been eating about 1500 calories a day...filled with lean meat, fish, and whole grains...most of the time i eat, half of my plate is atleast vegetables finished with some fruit for desert...i don't think i'm depriving myself...but i could be wrong...

my arms and abs are pretty sore...but i thought it was just because i started the rowing machine, and my body wasn't use to it...my friend said that muscle retain water when they're being worked out alot for the first time...could that be it?

I'm not sure if the muscles retaining water is true but you are definitely using muscles you haven't used in a while if you are sore... enjoy the newfound muscles :)

I remember reading somewhere that if your muscles are sore you will retain more water - something to do with inflamation?? (wish I could remember where it was).
I'm betting as soon as you get used to this new exercise the weight will fly off again
Good luck!

Are you sure that the weighscale calibration is ok? Or was previously ok? Otherwise, overnight increase of 4 lbs is unimaginable

If i remember correctly, muscle holds onto 3xs more water than fat does. Heck yea the rowing machine is what's doing it :)

Your muscles are probably swollen and you are holding onto water, no big deal, keep at it! I want a rowing machine:)

And if you're working out and burning extra calories with this new rowing machine, maybe you're not eating enough at 1500 cals. Ever think about that?  Maybe you need to increase if your body is holding onto weight due to under eating. Just another thought.