You've already used the HP so it won't hurt to call in. It will help to have a copy of the report they pulled, to discuss anything they mention as being a factor. What did they say in the letter as their reason for the denial?
How recently were the Lowes and Sams opened? And how old are the collections, and how many total? The collections are obviously your biggest hurdle. Calling in and politely explaining that you fell on hard times and that they were taken care of as soon as you could may help. It all depends on how nice of a rep you get really.
Laying low is never a bad idea, but since you already wasted the HP anyway, you should consider calling in and at least trying a recon. You really have nothing to lose.
Plus I think they use a proprietary score which wouldn't match your FICO.