How to differentiate water retention & fat gained?

I definitely did not over eat by 7000calories but I am just worried that it may be the calories accumulated because I might have been eating the wrong maintenance calories.

Then you have to make sure that you know what your correct calories are, log the correct calories and maybe weigh and measure your food to see if constant overeating ( even just a couple 100 calories) for whatever reason is the culprit. You are still in a phase when this can be easily remedied. Don't wait until you gained so much that you get discouraged.
Good Luck !

I definitely did not over eat by 7000calories but I am just worried that it may be the calories accumulated because I might have been eating the wrong maintenance calories.

Calories don't like accumulate in the stomach, and then get added all at once to cause a big weight gain.

After every single meal, once your liver glycogen stores are topped, once your muscle glycogen stores are topped off, once you've used extra carbs and any fat for immediate energy needs, once any protein has been used as needed, after that 3-5 hrs post meal you'll have stored any truly excess as fat.

So the difference that is very obvious - fast vs slow weight gain, or loss for that matter.

If you ate 250 calories over your true maintenance for 2 weeks - you would only gain 1 lb slowly if fat. And actually, if lifting, it wouldn't even be mostly fat.

Pick valid weigh-in days to minimize water weight changes.
Morning after rest day eating normal sodium levels, not sore from last workout.

That's about the best you can get.

Well...you don't gain 2 Lbs of fat overnight...so yeah...water.

Two Lbs of fat would be 7,000 calories...that would be 7,000 calories over your maintenance calories. Even then, the body is an amazing thing and you wouldn't actually put on 2 Lbs of fat if you did that. Overriding your body's ability to maintain requires consistent effort.

Your maintenance is going to be a range, not an exact number...your weight isn't static. You have water retention and release as well as timing of food in and out, etc. Hell, maybe you just need to take a big dump. You better wrap your head around this, or maintenance is going to be a real kick in the nuts.

Natural weight fluctuations can be 3-5 Lbs easily day to day.

Best thing you can do while in maintenance is to quit weighing yourself every single day. You'll go mad!

I agree. I sometimes get myself all freaked out over a couple lbs up and remember there are so many reasons weight can change all the time (food, water, sodium, BM regularity, hormones just to name a few). If you are maintaining maybe try weighing just once a week or every two weeks or something like that...daily you are likely to see fluctuations so you don't want to make yourself worry for nothing!

ps. congrats on getting to goal!

Best thing you can do while in maintenance is to quit weighing yourself every single day. You'll go mad!

I agree. I sometimes get myself all freaked out over a couple lbs up and remember there are so many reasons weight can change all the time (food, water, sodium, BM regularity, hormones just to name a few). If you are maintaining maybe try weighing just once a week or every two weeks or something like that...daily you are likely to see fluctuations so you don't want to make yourself worry for nothing!

ps. congrats on getting to goal!

But if I don't weigh myself daily I'm afraid that I'll gain back all the weight unknowingly...

Weekly, biweekly, monthly. You're not gonna magically blow up like a tick, I promise. Weigh yourself on a day when you feel good. Let go a little. You'll be a lot happier, and you're not gonna get fat.