Question about energy

Soooo I just joined here a few days ago and already have a question.
I started back on track on Sunday. I have been doing grea****ching my carbs, calories and drinking tons and tons of water (about 100 oz + up from about 40 oz a day). My  question is this: I woke up today completely exhausted. It takes more energy than I have to move around. I feel like I did a month post op 8 years ago. Is this normal? Is my body just trying to adjust to the limited diet and if that is it, is it limited carbs or calories do you think? And most importantly- will it go away and when?? I am getting 50g. or more of protein and plan to add in protein drinks today (I haven't done it until now because of the higher carbs in them).
HELP! I cannot function and just want to go back to bed- not something my 2 year old daughter (granddaughter I am raising) is ok with.
Oh and I am taking my vitamins and calcium. I also added some b-12 today. I used to be to high in levels on that so didn't take it much. I don't think it is lack of iron since I no longer have periods after a hysterectomy in '98.

I don't know if it's normal, but if you had RNY you may need more protein.  I use ISOPURE zero carb shake mix, Nectar, and Matrix.  They are all low to no carb...

When did you last time have Blood work? you need that.  If you feel tired - that may be god time to see your numbers.
Iron, B12, proteins, Thyroid,  - all of the above - when low - will make you really tired.
I am 2 years post op and my periods are mostly gone - but my iron was low. It was "low normal"  but that was enough to make me tired.  Low iron may affect the thyroids.
Also  low level of proteins will make you tired. Based on my results - I now take 100 + gr per day. 
Check your blood test.

But - since you just recently cut on carbs - your body may be reacting to it.  Give it a few days and see if you feel better- once your body gets used to low level of carbs.

I did make my appointment today to get my referral to see the new surgeon on my insurance plan. I have not had blood work done in a LONG time and I need to for sure. I may just add a extra iron in the meantime since it will be at least 6 weeks to get in with him once my referral goes through.. I upped my protein and maintained my carb level and still feel weak tonight but not as bad. I upped my calories today too since I only did 738 yesteday. I am wondering if that had an effect too. I normally do about 1200-1400 a day. I was not hungry at all (and I do get that way normally) but I do wonder... maybe my brain was happy with 738 calories but my body wasn't so sure.

Thanks for the feedback. I forgot how much having the support of others means.