Am I eating too little?

What are you eating on a daily basis, exactly?

edit; oops sorry, didn't know we can view people's diary!

I had a brief look at your diary. It looks to me like you're doing fine, but yesterday you were 432 calories under what MFP said you should eat. I believe their threshold for eating too little is likely around 400 calories under goal etc. remember, its an automated system and doesn't actually consider your whole lifestyle. I'd say based on the couple of days that I looked at that your calorie intake is pretty good based on your numbers.

I would strongly suggest weighing and measuring everything so you know you're being accurate with the logging, this will give you an accurate picture of what you're putting in and you won't have these fears.

Last night MFP warned me saying I wasn't eating enough, and I could put my body in starvation mode. But I don't feel like I'm starving myself... I'm usually under my calorie goal by a little bit. But I'm sure I mis-estimate somethings when entering quantities, so I feel like it balances out. Thoughts?

You might not be under your calorie goal by as much as you think because, to me, your exercise burns look overestimated. Where do you get your estimates from? MFP and machines generally tend to provide inflated numbers Other than this, it looks like you are eating well. It's the end week balance that counts. Everything is trial and error.

You are potentially eating too little if any of the following apply:

1. You are feeling unwell, weak or excessively tired. Longer term this can look like thinning hair, poor quality skin/nails, suffering with recurrent infections etc.
2. You are losing much more than 1% of your body weight weekly (assuming you have a reasonable amount of weight to lose, as you near goal that figure needs to reduce).
3. You are finding with your exercise/workout that you are struggling to progress (weights or cardio). If you are slower to hit 5k on a run as an example, or you are needing to drop/reduce resistance work (including weights) then that's your body's way of indicating you are cutting back too hard.

There is nothing wrong with varying your calorie intake if it suits you. If you wanted to lose 1lb per week some people do best to stay 500 calories per day under, others do better if they restrict by staying 700 calories under 5 days per week then "splashing out" and eating at maintenance at the weekends. What ever works for you, but for most people who have splash out days sticking to maintenance calories rather than scoffing well over maintenance helps to keep appetite levels reasonable and doesn't leave you with too wilder drop during the week.

Not sure where you are or how you are estimating your calories burned, but they seem WAY off