begining to run maybe

[DDH]

Hi girls,


I've been biking for a couple years now, but it's more for fitness and fun and trying to lose weight so when it's cold, or raining, or to windy I don't get to go. I have a treadmill at home, and I get on it and walk at 3.5 or 4 for 2 to 3 miles but I don't feel like I burn near as many calories as the bike so I want to start trying to run.

I have fought my weight since I had my son 13 years ago. I weighed about 180 after I had him, (I gained 70 lbs with him) horrible I know, and over the years even though I have tried several times to lose weight, I am now at 240-245.
Recently I have tried once again to get really serious about losing and have been documenting everything I eat. I am exercising daily with an ocasional day skipped because of appts and such for my MIL.
I am eating about 1000 to 1200 calories a day and the first 2 weeks I lost about 5 lbs. and then started my period, and that set me back because of cramping and eating to much. I know I have to learn to control that too.

Okay, long so let me shorten it. I want to start running and I have tried a few times so instead of walking fast at 4 mph, I will jog a bit and then I have kicked it up to 5 and 6 however I cannot breath after about 1 to 2 minutes depending on my speed. I even ran once at 10 mph for 15 seconds. LOL

How do I increase this, I feel like I am getting no better. Should I even be trying to run at my weight or am I looking at doing some damage to myself.
I love my bike, but I have to do something else along with it because the weather is just to unpredictable to depend soley on bike riding for exercise.

This week I think I gained back 2 of the lbs I lost because for two days I pigged out. I had a chocolate attack and couldn't stop. That is very unusal for me because normally I don't even eat chocolate, and snacking it not usually a problem for me, it's portion control.

Anyway, any help would be so appreciated.