Depressed confused drugs gambling

I'm 36 weeks pregnant and feelin so low. 
I no my partner has been takin drugs n he's also goin out at weird times and coming back after few hours.  I don't no what he's upto. I kind of suspect he's gambling but I have no proof. He did admit to gambling 15,000 last year but promised he wudnt do it again. He admitted as I had proof then but I have nothing now. When I ask he Denys point blank and then I think I'm being over suspicions. He denies takin weed but iv seem roll ups n green leafy things in the bin. So I'm not imagining it. 
 Iv been givin him the silent treatment because I don't no how to handle it. 
I have no one to talk to as everyone thinks so highly of him. I jus don't no wat approach to take now.  Some one advise me please. I hate being suspicious. We have 3 kids and one the way. I jus feel like crying