Hi K., Hang in there, it's hard to have a 19 month old and a 11 week old...and being a stay at home mom...I would guess you don't get a lot of help from family or friends. I've been in your shoes. I had to switch to a stronger anti-depressant through the later part of my breastfeeding to help control the anxiety and depression...and I just had to weigh out the benefits etc. I mean...sane mommy who's not in tears most of the day......or crazy mommy who can't stop crying and doesn't want to get out of bed. The slight chance that a little medication would pass through breast milk seemed minimal at the time..but I did have an older baby....11 weeks is still pretty young.
I would suggest doing some online research then going to a doctor to discuss it. I know personally a lot of the natural anti-anxiety things don't help me. Only through some intensive counseling in combination with some anti anxiety pills have I been able to find a balance..and hopefully not need the anit-anxiety pills forever.
I also want to suggest you look up a MOMs Club in your area...I think a support system might be part of your anxiety (it was for me..I felt very alone and isolated with a baby) being around other moms going through the same thing...could really help you out. good Mom's club....and then your city name....see what's in your area. The dues are like $25 a year...and they have WEEKLY activities like park days, craft days..etc...that they do. Even if you can't afford counseling at this time (that was my hang up for a while) joining a group of other moms might act as that counseling for you.
Then seek out advice from your doctor..there shouls be SOMETHING you can take while breastfeeding that has minimal pass through.
good luck. feel free to private message me anytime. I've been in your shoes...and not going to do the whole...no medication is best speel...because I know that didn't work for me. (I tried).