HELP! I want to lose weight not gain!

Open your diary.

And working out causes more muscle strain, which causes more nutrients and water to be stored in the muscle, thus more water retention. The body holds A LOT of water.

Consider not weighing yourself so much. Your weight can fluctuate pretty widely within a day, and between days. And your hormone cycle can affect the weight as well. Maybe pick one day out of the week to do it, and do it around the same time each weigh-in. You're less likely to be driven nuts if you measure yourself instead of weighing.

Not sure what you do as far as exercise, but maybe try to do more cardio -- get out and walk/jog for 30 minutes a day (4-5 days per week)...even just that will burn more calories and help keep your water weight from fluctuating so much.

** Also ....you're taking in A LOT of fat in your diet. It would almost be better to have a little bit less in your diet...might help with weight loss.

for the past four days my weight has continued to go up. What am I doing wrong?

Define "up". 1, 2, 3, 5 pounds? What's your exercise routine? Current weight and height? The more information you put out there the more ideas you'll get on what to do to correct this problem.

Questions if you let MFP set all values for you
1. What weight loss goal did you choose?

Questions if you set goals yourself
1. Why 1750 calories?
2. BMR?
3. TDEE at sedimentary?
4. How much are you looking to lose a week?

General questions
1. What type of exercise are you doing?
2. How much weight are you gaining?
3. How long have you been gaining?
4. How long have you been doing your exercise?

What is your BMR and TDEE? My TDEE is around 1,700. No way I could eat up to 2,100 calories a day and not gain. I think MFP overestimates calories burned as well and I only eat half my exercise calories.

You would have to eat 3500 calories over and above what you're burning to gain a pound of body fat. So, unless you've eaten an extra 14000 calories in the last 4 days, you haven't gained fat. You are most-likely gaining water weight. I just started back hard-core exercising and I'm seeing about a pound a day myself, but I know that it's just my sore muscles holding onto that water.

You can do a few things to try and reduce the amount of water you are retaining:

1) Lower your sodium. Try to get about 1600 mg a day and no more.
2) Don't eat added sugar. Every molecule of glycogen running around your body has 2 molecules of water attached to it. Processed sugars (cane and corn sugar) turn to glycogen faster than unprocessed sugars. (http://www.globalhealingcenter.com/sugar-problem/refined-sugar-the-sweetest-poison-of-all)

I also gree that you shouldn't weigh in every day. Once a week - at exactly the same time and wearing exactly the same thing is the best way to gauge your weight loss. (Naked, first thing in the morning after peeing)

And I gained about 4 pounds in 4 days

For the future, if you put on a few pounds in 4 days does that doesn't give you an idea if you're really continuously gaining or not. You'd have to eat an additional 14000 in 4 days on top of your 2300 a day to gain 4 in fat. So, it's unlikely you've put on this in fat. So, the likely culprit is water weight, which is sometimes needed in life. You'll lose it in a few days. If you work out allot, water can fluctuate allot.

Edit: I see Maintain4Life basically summed what I said up :P In case you don't know glycogen btw is a form of energy. Don't try to completely rid your body of it, it helps repair your muscles and gives your organs energy they need to live. But I'm not going to argue that real sugar > processed sugar. You can get glycogen all sorts of ways.