No progress- getting very frustrated

The first thing I would do is check my logging. Here's a list:
Are you logging everything, every bite, every meal?
Are you using a food scale? That will give you the most accurate idea of what you're eating, more than cups and spoons.
Do you eat out in restaurants or eat food prepared by other people? That can throw your calorie count off.
The MFP database is compiled by users and has many inaccuracies. The USDA entries are better than most. What entries do you use?

Your diary is closed. If you go into settings and make your diary public, people here might spot something and be able to help you.

If you've started new activity this can cause fluid retention (DOMS).
What about your sodium intake? If this is high you can retain water which causes the scale to go up.
How are your measuring your food (scale or cups/spoons)?
Just curious why you are drinking a gallon of water?
When you lost weight before what kind of diet were you following compared to what you are doing now?

There is always progress, even when you've gained weight.

I am actually in a similar situation as you explain here, with the same exact figures. I can completely understand how seeing the scale creep up makes you feel as if you are doing something wrong, or that you want to quit, or that you even hate yourself (maybe that is just me).

However, I keep in mind that there is always progress, and my worth and value is actually not dictated by how much weight I have gained or lost, although many ways of thinking will try to argue against that. When I start to look at myself more holistically, such as valuing other things, such as how much I am mentally and emotionally present and available during the day, if I meditated or spent quality time with myself, the tidiness of my home, whether I got outside, if I did any creative work, if I ate clean and honored my body, and so much more -- then I can say that I am not failing but even thriving even though the scale is not where I want it to be at this moment.

On a wellness journey, be sure that you take into consideration all of the factors and all of you. I have found that when other things in life line up and make you feel good and successful, the weight comes along for the ride.