Depression & Counselling. Help?

I'm an 18 year old college student. Since the past 2 years, I'm really lacking motivation to do something for myself. I'm mostly a lively person when I'm in a group of people, but when I'm alone, I feel sad, guilty, helpless and miserable for myself. I overthink a lot. I love to be around people but I rarely go out, and this worries my mother. She urges me to get involved in different activities, but none seem to impress me. I often speaking back to parents which they perceive as an argument against them, but that is not so. I feel my life is meaningless and don't have the interest in doing anything. I end up procrastinating a lot of my time and study last minute for exams. I want to change that but it's not happening. I really feel insecure about myself but I don't have anything to lose. I randomly break into tears anytime in the day and I cry myself to sleep.I also have suicidal thoughts I can't share this with anyone. Should I seek professional help? If yes, then please recommend.