How much do I overlook before it's too much, and am I right in how I feel?

My boyfriend and I have known each other for 7 years. We dated on and off a long time ago, and recently decided to try things again. He had a brief period of heavy drug use, but has been clean for many many months. Here lately, he's been tight on money and isn't making much at his job, so he was short on rent. He borrowed money from a friend to pay it, and is struggling to pay it back. I just found out that he's now selling drugs to make the extra money. He also tested some of the stuff to make sure it was "good." I'm extremly upset about this. I offered to give him the money to pay his friend back, but he refuses to take it. I know it's a pride thing; he's insisting that he wants to do it himself, but at what cost? All week he's been very distant, hasn't talked to me much, and just canceled a trip I've been planning for this weekend. This combined with the dealing thing have left me feeling extremely neglected and unvalued. I feel like he's picking that lifestyle over me, regardless of how I feel or the dangers involved. I love him like crazy...but I don't know if I can overlook this. It's not even so much what he's doing as how he has reacted to my feelings on it. It hurts worse that my feelings don't seem to matter. Am I overreacting, or am I justified in feeling this way?