What you're experiencing is not unusual for mast cell patients at first. If you cut back on activity and pace yourself with frequent breaks and not getting over-heated, you'll find you can build up your stamina. Right now, your body rebels when it gets stressed from any cause, emotional or physical, and that includes too much housework. It won't always be this way.
Part of recovery is figuring out how to do just a bit less than what triggers symptoms! Then you build on that. You can still do what you used to do, just not as much and not all in one session. Some things to try that helped me were:
Avoid heat as much as possible. It's a huge trigger! Do as much of your work before the heat of the day or later in the evening. Turn on the AC or a fan, wet a t-shirt or scarf and put it on, fill a spray bottle with ice water and spray yourself often, drink cool (or cold, if you can tolerate it) water all day long. Take a cool bath or shower.
Work for 10-15 minutes, then sit down and have a cool drink, play with the baby, read, watch TV, or whatever is relaxing. Then 15 more minutes. If that works, increase to 20. If it's too much, cut back to 10.
Prioritize. If no one's completely out of clean underwear, no need to do laundry today!
If the baby needs you, then the dusting can wait. If you can't clean the whole bathroom in one day, that's okay. Do just the one fixture that needs it the most.
Please know that you can build your stamina, and you WILL be able to do many things you used to do without reacting. It takes time and patience and faith and the right meds.
I would always try the usual oral meds before trying stronger ones, but if you have high IgE, Xolair might be very helpful.
Sorry if I've asked you this before, but have you had your vitamin levels checked? If you're not on a varied diet, and if you aren't processing foods normally, you could be a little anemic or have a vitamin or mineral deficiency. If you're not absorbing nutrients very well, it could make you feel tired. Dr. Afrin or your regular doc can order those tests.