Starting back in the gym need advise on how often etc

Hi, I'm just starting back in the gym as of last week and I have some time off for the next month and was wondering if I should go more often?

Here's where I'm at now. I've been overweight since I hit puberty and was about 18 stone when by time I was 18. I've always struggled with my weight and when I was 25 I finally kicked my arse enough and I got down from 15 and a half to 12 and a half stone. I was really happy and it took me about a year to get down with regular gym visits (three times a week) and a good diet plan.

However I got cocky when I started back in a college course about five years ago, I thought "Oh I'll never put that weight back on" and BOOM back up to 16 stone in about 3 months. just crept back before I noticed.

after finishing college I was unable to find a job and found myself just sitting about the house, I put on another two stone and a now 18 stone again. gutted but confident I can lose it again. so I started back in the gym about two weeks ago and I'm losing a steady 2 pounds a week by going monday, wednesday, friday. However I've been thinking that since I have some time off I might up that too five days a week.

I have the free time but I'm concerned that if I go five days a week I might strain something if I'm just starting off. would I be better to leave it at three days a week for the first few weeks or should I just barrel ahead?