Worried

Hello ladies. I have a topic I'd like some advice on. I have been trying to track my cycles for the past 6-8 months and they're SUPER irregular. Almost to the point where I can't even use this app to track. I've been thinking of trying to get pregnant again as we own our own home now so we are ready to expand our family (I already have one girl). The problem is I don't want to get on birth control because of the side effects. I've been super stressed about my self esteem because I've gained so much weight in the last 3 years...:( 
I'm worried if I go on birth control I'll gain even more, but I want another baby. I can't get pregnant with irregular cycles. They vary from like 22 days to 99 days. It's horrible. Any advice?