Help me please!!!!!!!!?

basically i have really really soft head, it used to be really hard about 2 months ago and i dunno why it has gone so soft. On an my shaft is rock hard but my head is really really soft (not like it used to be) and today i had for the first time it was going ok at first then i took it out and tried puttin it back in nd my head was just bendin back (i was hard) what isit? what should i of done should i of pushed really hard? please help and btw im 16 thanks.