I use aromasin and it is powerful. You've crashed your e2. I take 12.5 mg every third day on a similar protocol to what your using and I'm in the low 20's. When I was taking 12.5 mg daily I was at 7 for my e2 and had the same issues you are having.
I would have told you to wait until week 2 to start the AI and d 12.5 eod.
I'd say back off the AI until you get morning wood an your sex drive back and try 10mg eod.
Although aromasin has a short half life it is still working after 3 or so days until the body produces more aromatase enzyme.
Exemestane reaches peak plasma concentrations within 2 hours following the oral administration of a 25 mg dose. The active life of the drug is between 24 and 30 hours. This is significant since it is quite shorter than for the non-steroidal inhibitors. A single oral dose of 25 milligrams of exemestane causes a relatively long-lasting reduction in plasma and urinary estrogen levels, with maximal suppression occurring approximately 2 to 3 days after dosing and persists for about 4 to 5 days.It has been shown that 25 milligrams of exemestane is basically just as effective as 50 milligrams at suppressing estrogen, raising testosterone levels, and levels of IGF. It is therefore unnecessary to go higher in doses than 25 milligrams per day. Due to the active life of the compound exemestane should be administered roughly once every twenty-four hours. Users often start the drug on the first or second week of steroid use and continue to take it throughout the cycle and for a few weeks afterwards in order to prevent any type of estrogen rebound.