M.B.
You have your hands full. Lots of good comments. Here are some more.
1) You are in Houston. Call 211, this is a state/major city telephone number. Explain that you need assistance for your son, they can give you numbers for Easter Seals, United Way and other agencies that may have services to help you with Early Intervention Care ,which can bring people into your home to work with your son on speech and behavoir, occupation and physical therapy. There is no fee associated with the EIC program.
2) Talk to your doctor, ask if a) an anti depressant is appropriate, b) a handicap parking placard is appropriate.
3) Find a way to get some exercise..even if it is just walking around the neighbourhood with your son in a stroller, or something like that. Take him to the park, let him run supervised, get him on the swing.
My son had lost his speech, could not go to HEB/WalMart/Costco without screaming. His sensory neverous system was overloaded and overwhelmed. Through Easter Seals, we were able to have speech therapists and occupational therapists work with our son, and us, so that we could learn how to interact in a way that got him to communicate with us effectively, and help calm his sensory system. If you have a computer, I suggest getting Sesame Street learning programs that involve Elmo. Elmo seems to connect with kids who have sensory/speech/etc problems. Our son was ultimately diagnosed with Autism, but if you saw him today, 5 years later, you wouldn't think he was any different from the other kids in the playground or classroom. It has not been easy getting to this point.
3) Talk to your pediatrician and get a nutritioninst. Get a book called Children with Starving Minds..and evaluate what your diet and your families diet is. Many times allergies to wheat, corn, artificial sweeteners, corn/corn syrup can affect the behavior of our children. Give my guy corn syrup or wheat, and I have a monster who will not listen, who is hyper and aggressive. Get it out of his system, and my angel reappears. Also, check dairy...some react to it.
4) The anti-depressant, it is not a joke, and don't take it lightly. Getting a load of laundry done was a major accomplishment. My life was extremely overhwelming and I was exhausted with dealing with my child, my older son, my husband, my parents, and my father dying of cancer. Life is hard. When you are stressed out the hormone system is affected, your cortisol levels go up, you are constantly challenged to be ready to react to the next crisis, and your body is on a tightrope. There is a time to stop and seek help, physically and mentally. If you have a good relationship with your doctor, you can talk with him/her. If you don't, go find a better doctor, because what you are dealing with is not going to go away, it is going to get better, but there is a lot of work involved. Love your older children, give them hugs, lots of them, give them some moments of your time just for them, go to a movie, a show, a sport game, something, and let them know that there are moments of sunshine and love..you and they need it. Your younger one will get better and will survive your absence.
Good luck. Don't give up on your self. My doctor had beent alking to me for over a year about trying an antidepressant. I resisted. By the time I called and told the nurse I needed an appointment to talk with him about getting one, they called the pharmacy to get the rx that day, called me back to give me an appointment with the dr for the next day, told me to go pick up the rx NOW, and called me back in an hour to make sure I had gotten it. When I saw the dr the next day we had a laugh, then he told me that by the time people even think they need one, they are in trouble. The anti-depressant worke. I no longer felt overwhelmed, I could manage the demands on my mind and body and time, I stopped over reacting to my older child, and no longer had expectations of his behavior that were not age appropriate. There is a time to get off the drug, but not yet. And I know now just how hard things can be. You are not alone. You have more people than you can even begin to think of who have been where you are, and they are ok now. You will be too, but don't be so proud and stubborn to think you don't need help or there is no help. Make that call, talk to these people, get a case manager, and start working on a plan that will let you and your family live as a family, and get the help your baby needs.
God Bless.