I'm really sorry about this! I'm no expert but these are some things to consider.....
1. Will doing the MHS put you into (more?) debt?
2. What do you hope to achieve by doing the MHS? Do you think it will make a BIG difference in terms of what you want to be doing eventually? Is there another way to get to what you want to be doing eventually (ex. sit this year out, save money and improve your application, and apply again)?
If the MHS wouldn't put you into debt, then I think you should definitely consider it. But if it would put you into debt, then be VERY sure that it will get you where you want to go.
I guess my advice would be not to make a decision out of fear. Do you fear that you won't be able to get into a PhD program next year without this MHS? If this is the case, I would try to find a professor from your previous masters who could give you an objective opinion on your application and let you know whether an MHS would actually make a difference.
Of course, if your ultimate goal is to do a PhD at an Ivy League and nowhere else (just an example), then maybe going into debt is worth it.
Also, definitely try to find current MHS students to speak with. Hopkins has a great reputation, but I have heard that a lot of the faculty are inaccessible and that they accept a lot of students to the PH program so it's hard to build close relationships with faculty. Basically, check with current students if your expectations of what you want to get out of this MHS will be met.
Anyone else have additional thoughts?
PS It's interesting that you haven't received anything from Pitt. I think the acceptances went out, which means you might be on the waitlist.
PPS I assume you already have a master's. If you don't, then having one will definitely improve your application significantly for next year's PhD cycle.