stuck in a rut-help daily goal calories

disneyxx

so i had a profile before and then this one so ive been doing this approx 2 months and im in a bit of a rut and need advice

i weigh approx 123lbs - ive lost about 14lbs in that time, ive had about 4 days where ive ate way too much due to pizza-around 2100 calories in one day.

my calorie goal is set at 1200 calories a day but im really struggling to eat them as ive hugely cut back to around 700-800 calories a day and i exercise off around 250-300 calories a day through walking and stationary cycling, the thing that is stopping me eating the 1200 calories a day is the feeling of guilt , and im feeling worried that if i go from eating 700-800 calories a day to 1200 i will put weight back on.

im sitting here now and ive ate 568 calories and exercised 240 off today and all i want to do is go make myself two pieces of brown bread toast (210 cals worth) with Philadelphia (80ish cals worth) , but having a huge argument with myself telling myself ill pile on weight

im also starting marathon training on monday but still feel like i just cant eat the 1200 calories even though i will probably need them with 2 hours walking a day (walking the dog) and a hours run a day, due to the fear of putting on weight.

so basically i was just curious as too if anyone else has felt like this, eating very little calories and not being able to let yourself even eat your MFP recommended goal calories - feeling frustrated.