Thanks for asking. Regarding morning erections, it need not happen very frequently. In case of stress, one may not have morning erections, which is normal. There should be a concern if you are facing difficulties in sexual intercourse. That too for a month, and not occasionally. The age 38 as I see here, is not a worry for sexual dysfunctions. Obesity although is known to lower the sexual desire, but it does not cause Erectile problem.
Next Steps
I don't see a reason for concern. If you still want to have detailed and more information, you can also ask a direct query here on practo.
Health Tips
Do not worry.