It is very tricky for lots of people- yourself included, so don't feel alone. Re your questions"

How much time between sleeps and feeds should I spend actively playing with my baby? They
need about 1.5 hrs (I am guessing) between sleeps and the playing comes in when you dress, bathe, nappy change, feed him etc This is all valuable time to interact so do those things as you normally would and take your time doing them. Leaving him supervised on a mat for 10-15 mins is fine when you need a cuppa etc.

What little games can I play with him? I chat to him and show him all his toys but was wondering if there is anything more structured I should be doing? No, no no! You don't need structured play IMO with a bub. See above answer!Talk to him, explain what you are doing, what daddy is doing etc but not so you go mad. Just little chats.

Everyone just keeps telling me things will get worse as my baby starts to crawl and walk and get into everything and will be increasingly demanding of my attention, would you say this is the case? Is this the case until he goes of to kindy? (Dreading that day already!) Forget kindy time for now and think about the next couple of days ahead. Things don't get worse. But baby will demand more time and attention than a newborn and you will love and cherish every minute of it. I too gave up postgrad studies temporarily that I started before baby as baby just required so much time and attention that I was too tired and disinterested to study. You can only do so much and I just figured baby was my priority and once I established that (not hard!) everything fell into place and stress disappeared. Perhaps down the track you can get someone in for a few hours a week to mind your bub while you work from home?

Before baby I was a very confident, outgoing, social chic. But now when people invite me out or offer to look after my baby I just cant bear the thought! I know I will get over this one eventually, any tips on how to make the process less painful? How long did it take you to go on a night out or leave baby with someone? I still haven't got over this (and DD is coming up 2yrs) and to be honest I don't miss my night social life at all. I just don't leave DD with anyone and I don't go out at night except DH and DD come too which is very rare. My social life took on another form and is now a day social life that mostly includes people with chn or else it is all too hard for me. I found pregnancy, birth and the first year of motherhood was quite a confidence blow anyway as I struggled and couldn't cope with lack of sleep etc (all very normal stuff I since found out) but happy to say all is well again.
Sounds like you are doing a great job with your son so don't be hard on yourself!