I’m sure it is terrifying to feel so out of control. But I think you may have at least a bit more control than you think you do. The manic spending may have been triggered by the need to buy new clothes, but you are maintaining it by not confiding in your husband. That is a decision you are making. You can do much towards empowering yourself by deciding to talk to him instead.
I’m assuming that you have had a diagnosis of bipolar disorder before this, so it won’t be new information to your husband that you can get into a manic spin. Of course he will be disappointed. He may even be angry. But getting in deeper will only result in bigger disappointment and anger. Asking for help will get you back on the same team with your partner.
Then go back to therapy. Ask your doctor for a referral to a mental health counselor who specializes in bipolar disorders. Not all therapists are alike. Not every therapist is a good fit for every client. Interview a few therapists until you find one you can respect and stick with.
Meanwhile on a practical level: Make it more difficult for yourself to spend. Cut up credit cards. Take your name off your family bank account. Don’t go to stores. Don’t go online to catalogues. (If you can’t resist, make it difficult for yourself to get on a computer.) Confide in friends who may be shopping buddies and ask them to help you keep away from temptation. Ask your husband to take over the family finances for now. Ask him or a friend to take back anything that still has a tag on it.
If you can’t enlist the support of your husband, you have a different problem. Then the spending may be a way that you are putting distance between you and your husband. If that’s the case, you need marriage counseling as well as help for the manic state.
I wish you well.