You are doing way too much and eating far too little

I'd say even the weight you're at now is incredibly low, and if not already, then you'll start seeing adverse effects such as loss of period, hair loss, fatigue, etc... You're going to burn out.

I'm the same height and eat 15-1700 a day. I lift heavy 3x a week and aim for 7-10k steps a day. I'm 149lbs, and much smaller than I was at 144lbs last summer because I am growing muscle and you can even see my abs now and then.

Food is fuel. You need to go back up to maintenance by adding on 100 calories every week or two. I'm not sure how you're doing it tbh, but you're starving your body whilst overworking it.

You'll be amazed at how energetic you feel, you'll sleep better, feel less hungry and restricted. Gaining weight isn't the enemy.