Losing to much weight

I need some advice mammas. I exclusively breastfeed my daughter still. She eats every 3-3 1/2 hours during the day and she’ll sleep through the night. She also has 3 meals a day and some snacks in between. I’ve been under a lot of stress lately and my anxiety has also been pretty bad. Well I’ve lost 17 pounds in 4 months and I feel like that’s not very healthy for me considering I was at my ore pregnancy weight 3 weeks pp and the pounds keep coming off. I’m going to make a doctors appointment for next month to get some blood work done but I’m curious if any other moms have gone through this