Sounds like you're doing it a bit too intensely for a Newbie. You may want to ease up a little on the intensity.
I made an immediate gain of a half inch or so in a week or two and then nothing for two straight months--even though I kept increasing the intensity and length of my P.E. sessions. But most sites said it took three months to see results, so I kept at it, and, of course, that initial gain helped a lot. And my regained solid woodies was a HUGE factor for me to keep at it.