Any insight into whether this is too much or too little calories?

Hey everyone. I'm looking for some help losing weight. I used to lose weight fairly quickly whenever I added more exercise or watched what I ate but the past three weeks haven't shown much progress. I'm bummed because I only wanted to lose 6 lbs over a course of 8 weeks but I only have 4 weeks left. Here's a little about me:

• I love lifting weights, I hate cardio. But since I've been getting physical therapy for my shoulder I've stopped lifting because he wants me to rest my upper body. Because of this, I've been doing more cardio. Usually I do a Turbo Fire HIIT or 40 minutes between the elliptical and the bike at the gym. My HR is usually around 145 so I'm pushing pretty hard but nothing crazy. I usually work out a second time and do a class from Brazil Butt Lift or an ab workout (maybe a 20 min walk/jog)

• I have a job where I am constantly on my feet rushing around. I work as a phlebotomist at a fast paced plasma center and when I'm at work my HR is usually around 110 (according to my fitbit and confirmed by me). I take about 15,000 steps each day. Shifts are 8-10 hours long.

• Because of the workload at my job, my fitbit says I burn 3000 calories a day. This seems like a lot

• As of a month ago I completely cut soda out of my diet and I expected to see instant weight loss because I've been addict to cola for at least 6 years.

• I've been eating lots of raw, homecooked foods now too, although I will usually eat some kind of sweet treat every day. I know that's bad, but before I used to live off candy so I've cut a lot out.

• I am 5'5, 158 lbs and 25 years old. I am rather comfortable with my body but I am built like a softball player. I have pretty big muscles so the layer of fat I have over them make me look a little bulk.y

During this whole journey over the past 4 weeks I've been eating about 1800-2100 calories. Usually at least 110 g protein and around 220 g carbs. I am hesitant to go low carb because I am on my feet all day and don't want to lose energy. According to my fitbit this is a lot less than the calories I expend but I'm hesitant to eat 3000 at maintance because I feel like after working this job for many months my body is accustomed to the workload and must be gradually burning less each shift.

I don't think I'm eating too few because if that's the case I usually quickly drop 3-4 lbs and then plateau until I up my calories a bit, and I never dropped much of anything.

What do you guys think, eating too less, eating too much? I'm drinking 5 water bottles daily now (instead of a bottle of coke and one water bottle last month). Should I try low carb? Is my occasional candy splurge screwing me over even though I've cut back? Am I still at that stage where I'm just retaining water because I was fairly inactive (with the exception of work) before the past few weeks.