Advice?

This is a long post and I'm sorry, I feel like background information is necessary here. Please help.

When I was in high school, around 17, I discovered Blogilates: workout videos on Youtube. The whole Blogilates community was very welcoming and I was an avid follower of the monthly fitness calendars for around 10 months (March 2014 - November 2014). Nothing seemed to be happening, I wasn't losing weight despite my best efforts. I was using diet tracker My Fitness Pal to keep my calorie consumption at the low 1,200 calories I was allowed each day. Nothing was working.

December in retail means lots and lots of overtime. This was my first job and so I eagerly accepted more overtime to fund my not-very-interesting lifestyle. However, my shifts were very irregular meaning meal times were never at the right time. I work in a shopping centre where the only food options are McDonalds, KFC, Subway and Greggs. For the entire Christmas period, I consumed food from these fast food chains every day. I put on 1 stone.

For context, this is my weight tracking from My Fitness Pal:

March 2014: 8st 12lbs
April 2014: 8st 9lbs
July 2014: 8st 6lbs
August 2014: 8st 7lbs
Feb 2015: 9st 6lbs
April 2015: 9st 3lbs
July 2015: 9st 9lbs
Aug 2015: 9st 8lbs (an entire 1stone1lbs difference from 2014)
Oct 2015: 9st
March 2016: 8st 12lbs
May 2016: 8st 8.5lbs
Aug 2016: 8st 6lbs (the goal weight I put in to MFP)
Oct 2016: 8st 6lbs
Jan 2017: 8st 8lbs

As you can see, my weight has yo-yoed throughout the past 3 years. The summer of 2016 was definitely my healthiest; I was going to the gym 4-5 times a week as well as working retail (same job as 2014). Now I'm back at uni and fitting the gym around my studies is a lot harder and the gym isn't in a convenient place like my home gym is.

I hadn't been using MFP as much recently because this time round I was very happy with my body. July 2014 I was 8st 6lbs but with a lot of baby fat/ chubbiness, August 2016 I was (still am) the skinniest I've ever been.

Tonight, I went on to MFP and put in the food I'd eaten today (2 poached eggs on toast, a tuna sub roll from Greggs, a fruity cereal bar, BBQ rack of ribs with mexican rice) and it told me I was almost 800 calories over what I was allowed (my ribs were 840 calories alone).

My goals on MFP were set to 'Lose 1lb a week' with my goal weight being 8st 6lbs (I'm 8st 8lbs) and my settings were 'Not Very Active' as I changed it during essay season (8 hours sat at a library desk? wow.)

It got me thinking, are my goals right? Should I, a 20 year old female (5ft4) still be eating ONLY 1,200 calories a day? I am mostly happy with my body right now (I'd like to be more toned and maybe lose a bit more of the pouch I have).

I created a new account on MFP and changed the settings thinking that it might help. My new settings were
Weight: 8st 8lbs
Goal Weight: 8st 6lbs
Activity Level: Lightly Active
Goal: Lose 0.5lbs a week

And it told me I was allowed 1,570 calories per day. A quick Google search tells me that the average INACTIVE woman should eat 1,600 - 2,000 calories a day to maintain healthy weight. Should I stop using MFP or edit my goals to benefit me, even if they aren't my true goals?

I'm not entirely sure what I should do.