Good energy boosters

Drink water add 2 glasses to your day
High energy music get up and get dancing with those kids. Sounds silly but ups eeryones moods and energy level
Balanced diet. Track what you eat. Make it a good combo of veggies, grains proteins.
Are you in depression? Lethargy and weight gain and hopeless can be signs talk to doctor.

Just because your levels are all normal doesn't mean something isn't going on. I spent 3 years having every symptom of hypothyroidism possible going and still showing normal levels before it finally tanked enough to warrant medication. My suggestions are to look at your diet (like more non starchy veg), your sleep, and maybe consider this normal as being a single mom is exhausting (nevermind the added drama that your ex is bringing)! I'd also look at trying to cut out nonessential activities periodically.

That's all I can come up with without more information.

Just an outside thought - is your sleep quality good? Some research indicates sleeping with tv on, or checking cell phone during sleeping hours might lead to poor sleep.

I have gone through times where I was so exhausted all day that I could barely function. The key for me was having my doctor prescribe a sleep aid, which helped me fall asleep AND helped me get good quality sleep. It was a mild sedative, so if my kid was crying I'd still wake up and be able to tend to him. But I felt so much better the next day! This, in combination with an antidepressant, was very helpful for me. I wonder whether the Citalopram is contributing to your daytime fatigue. One possible side effect of that medication is drowsiness, and another is insomnia. Perhaps your doctor can help you address the mix of medications that could help. Good luck!