I think Michelle might be on to something.
You might be pushing his wake time too fast, try putting him down between an hour and 20 to an hour and 40.
You're going through a tough spot right now. Adjusted, your lo's age is 3.5 months, therefore you're just hitting the 45 min nap phase. Sit back, relax, and understand that it will pass. But it's not an easy phase to go through.
Mine did the exact same thing as your lo, and I reacted exactly as you are now. Screaming, crying until my DH got home; I would often call him at work in tears, and he would end up coming home early just to relieve me. I often ended up on the floor in a heap crying uncontrollably. I had a real problem obsessing about naps. I never left the house unless I absolutely had to. This was just a few weeks ago! This started at about the 3 month point and went on for weeks, as her naps progressively got worse.
Finally, last week I got help, went to see my psychiatrist. He put me on meds and treated it like PPD, and I can't believe the change. The day I started on meds she had a full day of 45 min naps...and I didn't freak! I was calm, collected, and I could think of what to do next. I can't tell you how amazed I was. She's had a pretty good week since then (with a few downs), but not once have I felt myself losing control of my emotions. TBH, I think being medicated helped her sleep. I wasn't as anxious and angry, and I knew she could sense that. Granted, the meds working the first day you start them isn't real typical, but then I've been on meds for depression and sleep for awhile, I just needed a change.
Anyway, just my story, thought it might help to know someone else has been there.
*HUGS*
Sonya =P